Use of IL-20 Antagonists for Treating Liver Diseases

ABSTRACT

Reducing liver fibrosis in a subject having or being suspected of having a liver disease using an IL-20 antagonist, which can be an antibody that blocks a signaling pathway mediated by IL-20. Such antibodies include anti-IL-20 antibodies and anti-IL-20R antibodies that specifically block the IL-20 signaling pathway.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser. No. 13/568,633, filed Aug. 7, 2012. The contents of the prior application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Chronic hepatocellular damage results in the development of liver fibrosis and subsequently liver cirrhosis. Liver fibrosis is the scarring process, in which extracellular matrix proteins, including collagens, accumulate in the liver for damage repair. Liver cirrhosis involves regeneration of nodules surrounded by fibrous bands. It is an advanced stage of liver fibrosis accompanied with distortion of the hepatic vasculature. While a number of therapeutic approaches for delaying the progression of liver cirrhosis or even reverse cirrhosis are currently being developed, liver transplantation remains the only curative option for treating live cirrhosis. Bataller et al., J Clin Invest, 2005, 115(2):209-18; and Schuppan et al., Lancet. 2008 371(9615):838-51.

Interleukin IL-20 (IL-20) is a member of the IL-10 family, which includes IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26. Blumberg, et al., 2001, Cell 104:9-19; Pestka et al., 2004, Annu Rev Immunol 22:929-979. IL-20 is expressed in monocytes, epithelial cells, and endothelial cells and acts on multiple cell types by activating a heterodimer receptor complex of either IL-20R1/IL-20R2 or IL-22R1/IL-20R2. Dumoutier, et al., 2001, J Immunol 167:3545-3549). IL-20 was found to be involved in various inflammatory diseases, such as psoriasis (Blumberg et al., 2001; Sa et al., 2007, J Immunol 178:2229-2240; and Wei et al., 2005, Clin Immunol 117:65-72), rheumatoid arthritis (Hsu, et al., 2006, Arthritis Rheum 54:2722-2733), atherosclerosis (Caligiuri, et al. 2006, Arterioscler Thromb Vasc Biol 26:1929-1930; and Chen et al., 2006, Arterioscler Thromb Vasc Biol 26:2090-2095), ischemic stroke (Chen et al., 2009, J Immunol 182:5003-5012), and renal failure (Li et al., 2008, Genes Immun 9:395-404). See also Wei et al., 2006, J Biomed Sci 13:601-612.

SUMMARY OF THE INVENTION

The present disclosure is based on the unexpected discoveries that IL-20 might be involved in the pathogenesis of liver fibrosis and antibodies binding to human IL-20 or human IL-20 receptor subunit R1 successfully inhibited liver fibrosis in mice suffering from liver injury.

Accordingly, one aspect of the present disclosure relates to a method for alleviating liver fibrosis or delaying liver fibrosis onset in a subject, comprising administering to a subject in need thereof an effective amount of an IL-20 antagonist. In some embodiments, the IL-20 antagonist is an antibody that inhibits a signaling pathway mediated by IL-20, such as an antibody that binds to an IL-20 protein (e.g., human IL-20) or an antibody that binds to an IL-20 receptor (e.g., human IL-20 receptor). Any of the antibodies used in the method described herein can be a full-length antibody or an antigen-binding fragment thereof. Alternatively, the antibody can be a human antibody, a humanized antibody, a chimeric antibody, or a single-chain antibody.

When an antibody that binds human IL-20 is used in the method described herein, it can be the monoclonal antibody mAb7E, an antigen-binding fragment thereof, or a functional variant thereof. In one example, a functional variant of mAb7E comprises the same complementary determining regions (CDRs) as mAb7E. In another example, the functional variant is a humanized antibody of mAb7E. Such a humanized antibody can comprises a heavy chain variable region (V_(H)), which comprises the amino acid sequence of SEQ ID NO:8, and a light chain variable region (V_(L)), which comprises the amino acid sequence of SEQ ID NO:12 or SEQ ID NO:13.

Alternatively, an antibody that binds a human IL-20 receptor, e.g., binds the IL-20R1 subunit, the IL-20R2 subunit, the IL-20R1/R2 complex, the IL-22R1 subunit, or the IL-22R1/IL-20R2 complex, can be used in the method described herein. In some embodiments, the antibody binds subunit R1 of human IL-20 receptor. Such an antibody can be a full-length antibody or an antigen-binding fragment thereof. It also can be a human antibody, a humanized antibody, a chimeric antibody, or a single-chain antibody. In one example, the antibody that binds subunit R1 of the human IL-20 receptor is an antibody comprising the same V_(H) and V_(L) as monoclonal antibody mAb51D or mAb7GW, or a functional variant of mAb51D or mAb7GW. A functional variant can comprise the same complementary determining regions (CDRs) as mAb51D or mAb7GW. Alternatively, a functional variant can be a humanized antibody of mAb51D or mAb7GW.

The subject to be treated in the method described herein (e.g., a method in which an antibody that inhibits the IL-20 signaling pathway is used) can be a patient (e.g., a human patient) who has or is suspected of having liver fibrosis, which can be associated with a chronic liver disease, such as chronic HBV infection, chronic HCV infection, alcohol abuse, nonalcoholic steatohepatitis, autoimmune hepatitis, primary biliary cirrhosis, fatty liver disease, or an idiopathic liver disease. In some examples, the subject is a human patient who has or is suspected of having liver cirrhosis.

Also within the scope of this disclosure are (a) pharmaceutical compositions for use in alleviating liver fibrosis or delaying the onset of liver fibrosis in a subject, the pharmaceutical composition comprising one or more of the IL-20 antagonists described herein (e.g., an antibody that inhibits the IL-20 signaling pathway such as an antibody that binds human IL-20 or human IL-20 receptor (R1, R2, or a complex thereof); and (b) uses of the just-described pharmaceutical composition in manufacturing a medicament for alleviating or delaying the onset of liver fibrosis/cirrhosis.

The details of one or more embodiments of the invention are set forth in the description below. Other features or advantages of the present invention will be apparent from the following drawings and detailed description of several embodiments, and also from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are first described.

FIG. 1 is a chart showing the inhibitory effect of mAb7E and mAb51D on TGF-β expression in rat hepatocyte cell line Clone-9 as determined by real-time PCR.

FIG. 2 is a chart showing the inhibitory effects of mAb7E and mAb51D on the expression levels of TGF-β (panel A), TNF-α, (panel B), and Col-I (panel C) in activated rHSC cells via real-time PCR.

FIG. 3 is a chart showing the protective effects of mAb7E and mAb51D on short-term CCl₄-induced liver injury. Panel A: a chart showing the serum levels of ALT in mice having CCl₄-induced short-term liver injury at various time points after CCl₄ treatment. Panel B: a chart showing the serum levels of AST in mice having CCl₄-induced short-term liver injury at various time points after CCl₄ treatment.

FIG. 4 is a chart showing the protective effects of mAb7E and mAb51D on long-term CCl₄-induced liver injury. Panel A: a chart showing the serum levels of ALT in mice having CCl₄-induced long-term liver injury at various time points after CCl₄ treatment. Panel B: a chart showing the serum levels of AST in mice having CCl₄-induced long-term liver injury at various time points after CCl₄ treatment.

BRIEF DESCRIPTION OF THE SEQUENCES

SEQ ID NO:1 is the nucleotide sequence encoding the heavy chain variable region of monoclonal antibody mAb7E.

SEQ ID NO:2 is the amino acid sequence of the heavy chain variable region of monoclonal antibody mAb7E.

SEQ ID NO:3 is the nucleotide sequence encoding the light chain variable region of monoclonal antibody mAb7E.

SEQ ID NO:4 is the amino acid sequence of the light chain variable region of monoclonal antibody mAb7E.

SEQ ID NO:5 is the nucleotide sequence encoding the heavy chain variable region of humanized antibodies HL1 and HL2 derived from mAb7E (precursor form, which includes a signal peptide).

SEQ ID NO:6 is the amino acid sequence of the heavy chain variable region of humanized antibodies HL1 and HL2 derived from mAb7E (precursor form, which includes a signal peptide).

SEQ ID NO:7 is the nucleotide sequence encoding the heavy chain variable region of humanized antibodies HL1 and HL2 derived from mAb7E (mature form, lacking the signal peptide).

SEQ ID NO:8 is the amino acid sequence of the heavy chain variable region of humanized antibodies HL1 and HL2 derived from mAb7E (mature form, lacing the signal peptide).

SEQ ID NO:9 is the nucleotide sequence encoding the light chain variable region of humanized antibody HL2 (precursor form, which includes a signal peptide).

SEQ ID NO:10 is the amino acid sequence of the light chain variable region of humanized antibody HL2 (precursor form, which includes a signal peptide).

SEQ ID NO:11 is the nucleotide sequence encoding the light chain variable region of humanized antibody HL2 (mature form, lacking the signal peptide).

SEQ ID NO:12 is the amino acid sequence of the light chain variable region of humanized antibody HL2 (mature form, lacking the signal peptide).

SEQ ID NO:13 is the amino acid sequence of the light chain variable region of humanized antibody HL1 (mature form, lacking the signal peptide).

SEQ ID NO:14 is the amino acid sequence of the heavy chain of monoclonal antibody mAb7GW.

SEQ ID NO:15 is the nucleotide sequence encoding the heavy chain of monoclonal antibody mAb7GW.

SEQ ID NO:16 is the amino acid sequence of the light chain of monoclonal antibody mAb7GW.

SEQ ID NO:17 is the nucleotide sequence encoding the light chain of monoclonal antibody mAb7GW.

SEQ ID NO:18 is the amino acid sequence of the heavy chain of monoclonal antibody mAb51D.

SEQ ID NO:19 is the nucleotide sequence encoding the heavy chain of monoclonal antibody mAb51D.

SEQ ID NO:20 is the amino acid sequence of the light chain of monoclonal antibody mAb51D.

SEQ ID NO:21 is the nucleotide sequence encoding the light chain of monoclonal antibody mAb51D.

DETAILED DESCRIPTION OF THE INVENTION

The cellular and molecular mechanisms of liver fibrosis development have been suggested in the last decade. Hepatic stellate cell (HSCs) are considered as the main cell population that plays the critical role in increasing deposition of extracellular matrix protein (ECM) in the liver, leading to liver fibrosis. HSCs must be activated such that they are converted from resting, fat-storing cells to myofibroblasts-like cells, which are capable of synthesizing a broad spectrum of extracellular matrix proteins. Stella cell activation is the central event in haptic fibrosis. HSC activation consists of two major phases: the initiation stage and the perpetuation stage. The former refers to early paracrine-mediated changes in gene expression and phenotypes that render the cells responsive to other cytokines and stimuli. Subsequently, the initially activated HSCs enter into the perpetuation stage, in which the cells maintain the activated status and produce various ECM proteins, leading to liver fibrosis. In addition to HSCs activation, TGF-β production of hepatocytes also plays an important role in the pathogenesis of liver fibrosis because it is a potent fibrogenic factor responsible for liver fibrosis.

The present disclosure reports the unexpected discoveries that (i) IL-20 may be involved in the pathogenesis of liver fibrosis via enhancing HSC activation and elevating TGF-β production in hepatocytes; and (ii) antibodies capable of interfering with the IL-20 signaling pathway (e.g., mAb7E and mAb51D) successfully reversed the fibrogenic effects of IL-20 in a liver fibrosis animal model. Accordingly, the present disclosure relates to methods of treating liver fibrosis (e.g., alleviating liver fibrosis or delaying the onset of liver fibrosis) in a subject using an effective amount of an IL-20 antagonist, which can be an antibody capable of interfering with the IL-20 signaling pathway.

General Techniques

The practice of the present invention will employ, unless otherwise indicated, conventional techniques of molecular biology (including recombinant techniques), microbiology, cell biology, biochemistry and immunology, which are within the skill of the art. Such techniques are explained fully in the literature, such as, Molecular Cloning: A Laboratory Manual, second edition (Sambrook, et al., 1989) Cold Spring Harbor Press; Oligonucleotide Synthesis (M. J. Gait, ed., 1984); Methods in Molecular Biology, Humana Press; Cell Biology: A Laboratory Notebook (J. E. Cellis, ed., 1998) Academic Press; Animal Cell Culture (R. I. Freshney, ed., 1987); Introduction to Cell and Tissue Culture (J. P. Mather and P. E. Roberts, 1998) Plenum Press; Cell and Tissue Culture: Laboratory Procedures (A. Doyle, J. B. Griffiths, and D. G. Newell, eds., 1993-8) J. Wiley and Sons; Methods in Enzymology (Academic Press, Inc.); Handbook of Experimental Immunology (D. M. Weir and C. C. Blackwell, eds.); Gene Transfer Vectors for Mammalian Cells (J. M. Miller and M. P. Calos, eds., 1987); Current Protocols in Molecular Biology (F. M. Ausubel, et al., eds., 1987); PCR: The Polymerase Chain Reaction, (Mullis, et al., eds., 1994); Current Protocols in Immunology (J. E. Coligan et al., eds., 1991); Short Protocols in Molecular Biology (Wiley and Sons, 1999); Immunobiology (C. A. Janeway and P. Travers, 1997); Antibodies (P. Finch, 1997); Antibodies: a practical approach (D. Catty., ed., IRL Press, 1988-1989); Monoclonal antibodies: a practical approach (P. Shepherd and C. Dean, eds., Oxford University Press, 2000); Using antibodies: a laboratory manual (E. Harlow and D. Lane (Cold Spring Harbor Laboratory Press, 1999); The Antibodies (M. Zanetti and J. D. Capra, eds., Harwood Academic Publishers, 1995).

IL-20 antagonists and Pharmaceutical Compositions Comprising Such

IL-20 is a pro-inflammatory cytokine that belongs to the IL-10 cytokine family. The IL-20 described herein refers to interleukin-20 and variants thereof that retain at least part of the activity of IL-20. As used herein, IL-20 includes all mammalian species of native sequence IL-20, including human, canine, feline, equine, or bovine. In one example, the IL-20 is a human IL-20 (GenBank accession no. NP_(—)061194.2).

IL-20 activates the IL-20 signaling pathway via binding to IL-20 receptor, which is a dimeric complex contains subunits IL-20R1 and IL-20R2 (also known as RA and RB). Such an IL-20 receptor is shared by three functionally different cytokines, i.e., IL-19, IL-20, and IL-24, suggesting that this receptor mediates different signaling pathways dependent upon its binding to a specific cytokine. IL-20 is also capable of binding to a dimeric complex containing IL-20R2 and IL-22R1. The IL-20 receptor disclosed herein refers to one or more polypeptides that are capable of binding to and being activated by IL-20. IL-20 receptors disclosed herein include IL-20R1, IL-20R2 and IL-22R1 of any mammalian species, including, but are not limited to, human, canine, feline, equine, primate, or bovine. Examples of human IL-20 receptors include hIL-20R1 (GenBank Accession No. NM_(—)014432.2), hIL-20R2 (GenBank Accession No. NM_(—)144717.2) and hIL-22R1 (NM_(—)181309.1). Sequences of human IL-20 receptors have been described; for example, in U.S. Pat. Nos. 6,610,286; 7,122,632; 7,393,684; and 7,537,761; and U.S. Pat. App. Pub. Nos. 2006/0263850 A1; 2006/0263851 A1; 2008/0247945 A1, and 2009/0074661 A1.

The IL-20 antagonist to be used in the methods described herein is a molecule that blocks, suppresses, or reduces (including significantly) the biological activity of IL-20, including downstream pathways mediated by IL-20 signaling, such as receptor binding and/or elicitation of a cellular response to IL-20. See US2011/0064731, which is incorporated by reference herein in its entirety. The term “antagonist” implies no specific mechanism of biological action whatsoever, and is deemed to expressly include and encompass all possible pharmacological, physiological, and biochemical interactions with IL-20 whether direct or indirect. For purpose of the present disclosure, it will be explicitly understood that the term “antagonist” encompass all the previously identified terms, titles, and functional states and characteristics whereby the IL-20 itself (e.g., human IL-20), an IL-20 biological activity (including but not limited to its ability to mediate any aspect of liver fibrosis), or the consequences of the biological activity, are substantially nullified, decreased, or neutralized in any meaningful degree, e.g., by at least 20%, 50%, 70%, 85%, 90%, 100%, 150%, 200%, 300%, or 500%, or by 10-fold, 20-fold, 50-fold, 100-fold, 1000-fold, or 10⁴-fold.

Exemplary IL-20 antagonists include, but are not limited to, an anti-IL-20 antibody, an anti-sense nucleic acid molecule directed to an IL-20 (including an anti-sense nucleic acid directed to a nucleic acid encoding IL-20), a small interfering RNA (siRNA) directed toward an IL-20 nucleic acid, a microRNA directed toward an IL-20 nucleic acid, an IL-20 inhibitory compound, an anti-IL-20R antibody (e.g., an antibody specifically binds IL-20R1, IL-20R2, or the dimeric complex formed thereby), an antisense nucleic acid molecule directed to a subunit of an IL-20 receptor, an siRNA or a microRNA directed to a nucleic acid encoding a subunit of an IL-20 receptor, or an IL-20R inhibitory compound. In some embodiments, an IL-20 antagonist binds IL-20 or IL-20 receptor and prevents the formation of IL-20-IL-20R complex, thereby inhibiting the IL-20 signaling pathway. In other embodiments, an IL-20 antagonist inhibits or reduces IL-20 synthesis and/or production (release). Such antagonists include antisense molecules, siRNAs and microRNAs.

Antibodies Capable of Interfering with the IL-20 Signaling Pathway

An antibody (interchangeably used in plural form) is an immunoglobulin molecule capable of specific binding to a target, such as a carbohydrate, polynucleotide, lipid, polypeptide, etc., through at least one antigen recognition site, located in the variable region of the immunoglobulin molecule. As used herein, the term “antibody” encompasses not only intact (i.e., full-length) polyclonal or monoclonal antibodies, but also antigen-binding fragments thereof (such as Fab, Fab′, F(ab′)₂, Fv), single chain (scFv), mutants thereof, fusion proteins comprising an antibody portion, humanized antibodies, chimeric antibodies, diabodies, linear antibodies, single chain antibodies, multispecific antibodies (e.g., bispecific antibodies) and any other modified configuration of the immunoglobulin molecule that comprises an antigen recognition site of the required specificity, including glycosylation variants of antibodies, amino acid sequence variants of antibodies, and covalently modified antibodies. An antibody includes an antibody of any class, such as IgD, IgE, IgG, IgA, or IgM (or sub-class thereof), and the antibody need not be of any particular class. Depending on the antibody amino acid sequence of the constant domain of its heavy chains, immunoglobulins can be assigned to different classes. There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, and several of these may be further divided into subclasses (isotypes), e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2. The heavy-chain constant domains that correspond to the different classes of immunoglobulins are called alpha, delta, epsilon, gamma, and mu, respectively. The subunit structures and three-dimensional configurations of different classes of immunoglobulins are well known.

The antibodies to be used in the methods described herein can be murine, rat, human, or any other origin (including chimeric or humanized antibodies). In some examples, the antibody comprises a modified constant region, such as a constant region that is immunologically inert, e.g., does not trigger complement mediated lysis, or does not stimulate antibody-dependent cell mediated cytotoxicity (ADCC). ADCC activity can be assessed using methods disclosed in U.S. Pat. No. 5,500,362. In other embodiments, the constant region is modified as described in Eur. J. Immunol. (1999) 29:2613-2624; PCT Application No. PCT/GB99/01441; and/or UK Patent Application No. 9809951.8.

Any of the antibodies described herein can be either monoclonal or polyclonal. A “monoclonal antibody” refers to a homogenous antibody population and a “polyclonal antibody” refers to a heterogenous antibody population. These two terms do not limit the source of an antibody or the manner in which it is made.

In one example, the antibody used in the methods described herein is a humanized antibody. Humanized antibodies refer to forms of non-human (e.g. murine) antibodies that are specific chimeric immunoglobulins, immunoglobulin chains, or antigen-binding fragments thereof that contain minimal sequence derived from non-human immunoglobulin. For the most part, humanized antibodies are human immunoglobulins (recipient antibody) in which residues from a complementary determining region (CDR) of the recipient are replaced by residues from a CDR of a non-human species (donor antibody) such as mouse, rat, or rabbit having the desired specificity, affinity, and capacity. In some instances, Fv framework region (FR) residues of the human immunoglobulin are replaced by corresponding non-human residues. Furthermore, the humanized antibody may comprise residues that are found neither in the recipient antibody nor in the imported CDR or framework sequences, but are included to further refine and optimize antibody performance. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are those of a human immunoglobulin consensus sequence. The humanized antibody optimally also will comprise at least a portion of an immunoglobulin constant region or domain (Fc), typically that of a human immunoglobulin. Antibodies may have Fc regions modified as described in WO 99/58572. Other forms of humanized antibodies have one or more CDRs (one, two, three, four, five, six) which are altered with respect to the original antibody, which are also termed one or more CDRs “derived from” one or more CDRs from the original antibody. Humanized antibodies may also involve affinity maturation.

In another example, the antibody described herein is a chimeric antibody, which can include a heavy constant region and a light constant region from a human antibody. Chimeric antibodies refer to antibodies having a variable region or part of variable region from a first species and a constant region from a second species. Typically, in these chimeric antibodies, the variable region of both light and heavy chains mimics the variable regions of antibodies derived from one species of mammals (e.g., a non-human mammal such as mouse, rabbit, and rat), while the constant portions are homologous to the sequences in antibodies derived from another mammal such as human. In some embodiments, amino acid modifications can be made in the variable region and/or the constant region.

In some examples, the antibody disclosed herein specifically binds a target antigen, such as human IL-20 or one of the two subunits of a human IL-20 receptor (e.g., IL-20R1). An antibody that “specifically binds” (used interchangeably herein) to a target or an epitope is a term well understood in the art, and methods to determine such specific binding are also well known in the art. A molecule is said to exhibit “specific binding” if it reacts or associates more frequently, more rapidly, with greater duration and/or with greater affinity with a particular target antigen than it does with alternative targets. An antibody “specifically binds” to a target antigen if it binds with greater affinity, avidity, more readily, and/or with greater duration than it binds to other substances. For example, an antibody that specifically (or preferentially) binds to an IL-20 epitope is an antibody that binds this IL-20 epitope with greater affinity, avidity, more readily, and/or with greater duration than it binds to other IL-20 epitopes or non-IL-20 epitopes. It is also understood by reading this definition that, for example, an antibody that specifically binds to a first target antigen may or may not specifically or preferentially bind to a second target antigen. As such, “specific binding” or “preferential binding” does not necessarily require (although it can include) exclusive binding. Generally, but not necessarily, reference to binding means preferential binding.

Antibodies capable of interfering with the IL-20 signaling pathway can be an antibody that binds an IL-20 (e.g., a human IL-20) and inhibits IL-20 biological activity and/or downstream pathways mediated by IL-20. Alternatively, such antibodies can be antibodies that bind an IL-20 receptor (IL-20R), e.g., bind to one or both of the subunits of the IL-20 receptor, and suppress the downstream signaling pathways mediated by the receptor triggered by IL-20.

(i) Anti-IL-20 Antibodies

An anti-IL-20 antibody is an antibody capable of binding to IL-20 and inhibits IL-20 biological activity and/or downstream pathway(s) mediated by IL-20 signaling. In some examples, an anti-IL-20 antibody used in the methods described herein suppresses the IL-20 signaling pathway by at least 20%, at least 40%, at least 50%, at least 75%, at least 90%, at least 100%, or by at least 2-fold, at least 5-fold, at least 10-fold, at least 20-fold, at least 50-fold, at least 100-fold, or at least 1000-fold. Examples of anti-IL-20 antibodies include, but are not limited to, those disclosed in U.S. Pat. Nos. 7,435,800; 7,115,714; 7,119,175; 7,151,166; and 7,393,684; and PCT publications WO 2007/081465; WO 99/27103; WO 2004/085475; and WO 2005052000.

The binding affinity of an anti-IL-20 antibody to IL-20 (such as human IL-20) can be less than any of about 100 nM, about 50 nM, about 10 nM, about 1 nM, about 500 pM, about 100 pM, or about 50 pM to any of about 2 pM. Binding affinity can be expressed K_(D) or dissociation constant, and an increased binding affinity corresponds to a decreased K_(D). One way of determining binding affinity of antibodies to IL-20 is by measuring binding affinity of monofunctional Fab fragments of the antibody. To obtain monofunctional Fab fragments, an antibody (for example, IgG) can be cleaved with papain or expressed recombinantly. The affinity of an anti-IL-20 Fab fragment of an antibody can be determined by surface plasmon resonance (BIAcore3000™ surface plasmon resonance (SPR) system, BIAcore, INC, Piscaway N.J.). Kinetic association rates (k_(on)) and dissociation rates (k_(off)) (generally measured at 25° C.) are obtained; and equilibrium dissociation constant (K_(D)) values are calculated as k_(off)/k_(on).

In some embodiments, the antibody binds human IL-20, and does not significantly bind an IL-20 from another mammalian species. In some embodiments, the antibody binds human IL-20 as well as one or more IL-20 from another mammalian species. In still other embodiments, the antibody binds IL-20 and does not significantly cross-react with other cytokines (such as the related cytokines IL-10, IL-17A, IL-19, IL-22, IL-24 and IL-26). The epitope(s) bound by the antibody can be continuous or discontinuous.

In some embodiments, the anti-IL-20 antibody described herein is anti-IL-20 antibody 7E, which refers to monoclonal antibody mAb 7E and its functional variants. MAb 7E is produced by the hybridoma cell line deposited at the American Type Culture Collection, 10801 University Boulevard, Manassas, Va. 20110-2209, U.S.A. and assigned a deposit number PTA-8687. This hybridoma cell line will be released to the public irrevocably and without restriction/condition upon granting a US patent on this application, and will be maintained in the ATCC for a period of at least 30 years from the date of the deposit for the enforceable life of the patent or for a period of 5 years after the date of the most recent.

The amino acid sequences and encoding nucleotide sequences of the heavy chain variable region (V_(H)) and light chain variable region (V_(L)) of mAb7E are produced below:

Nucleotide sequence (SEQ ID NO: 1) and amino acid sequence (SEQ ID NO: 2) of mAb 7E heavy chain variable region gaa ttg aag ctt gag gag tct gga gga ggc ttg gtg cag cct gga  45  E   L   K   L   E   E   S   G   G   G   L   V   Q   P   G  15 gga tcc atg aaa ctc tct tgt gct gcc tct gga ttc act ttt agt  90  G   S   M   K   L   S   C   A   A   S   G   F   T   F   S  30 gac gcc tgg atg gac tgg gtc cgc cag tct cca gag aag ggg ctt 135  D   A   W   M   D   W   V   R   Q   S   P   E   K   G   L  45 gag tgg att gct gaa att aga agc aaa gct aat aat tat gca aca 180  E   W   I   A   E   I   R   S   K   A   N   N   Y   A   T  60 tac ttt gct gag tct gtg aaa ggg agg ttc acc atc tca aga gat 215  Y   F   A   E   S   V   K   G   R   F   T   I   S   R   D  75 gat tcc aaa agt ggt gtc tac ctg caa atg aac aac tta aga gct 270  D   S   K   S   G   V   Y   L   Q   M   N   N   L   R   A  90 gag gac act ggc att tat ttc tgt acc aag tta tca cta cgt tac 315  E   D   T   G   I   Y   F   C   T   K   L   S   L   R   Y 105 tgg ttc ttc gat gtc tgg ggc gca ggg acc acg gtc acc gtc tcc 360  W   F   F   D   V   W   G   A   G   T   T   V   T   V   S 120 tca 363  S 121 Nucleotide sequence (SEQ ID NO: 3) and amino acid sequence (SEQ ID NO: 4) of mAb 7E light chain variable region gat ttt gtg atg acc cag act cca ctc act ttg tcg gtt acc att  45  D   F   V   M   T   Q   T   P   L   T   L   S   V   T   I  15 gga caa cca gcc tcc atc tct tgc aag tca agt cag agc ctc ttg  90  G   Q   P   A   S   I   S   C   K   S   S   Q   S   L   L  30 gat agt gat gga aag aca tat ttg aat tgg ttg tta cag agg cca 135  D   S   D   G   K   T   Y   L   N   W   L   L   Q   R   P  45 ggc cag tct cca aag cac ctc atc tat ctg gtg tct aaa ctg gac 180  G   Q   S   P   K   H   L   I   Y   L   V   S   K   L   D  60 tct gga gtc cct gac agg ttc act ggc agt gga tca ggg acc gat 215  S   G   V   P   D   R   F   T   G   S   G   S   G   T   D  75 ttc aca ctg aga atc agc aga gtg gag gct gag gat ttg gga gtt 270  F   T   L   R   I   S   R   V   E   A   E   D   L   G   V  90 tat tat tgc tgg caa agt aca cat ttt ccg tgg acg ttc ggt gga 315  Y   Y   C   W   Q   S   T   H   F   P   W   T   F   G   G 105 ggc acc aag ctg gaa atc aaa cgg 339  G   T   K   L   E   I   K   R 113

A functional variant (equivalent) of mAb7E has essentially the same epitope-binding specificity as mAb7E and exhibits at least 20% (e.g., 30%, 40%, 50%, 60%, 70%, 80%, 90%, or greater) of the activity of neutralizing a signaling pathway mediated by IL-20 as relative to mAb7E. In some embodiments, a functional variant of mAb7E contains the same regions/residues responsible for antigen-binding as mAb7E, such as the same specificity-determining residues in the CDRs or the whole CDRs. The regions/residues that are responsible for antigen-binding can be identified from amino acid sequences of the heavy chain/light chain sequences of mAb7GW or mAb51D (shown above) by methods known in the art. See, e.g., www.bioinf.org.uk/abs; Almagro, J. Mol. Recognit. 17:132-143 (2004); and Chothia et al., J. Mol. Biol. 227:799-817 (1987).

In addition, determination of CDR regions in an antibody is well within the skill of the art. There are at least two techniques for determining CDRs: (1) an approach based on cross-species sequence variability (i.e., Kabat et al. Sequences of Proteins of Immunological Interest, (5th ed., 1991, National Institutes of Health, Bethesda Md.)); and (2) an approach based on crystallographic studies of antigen-antibody complexes (Chothia et al. (1989) Nature 342:877; Al-lazikani et al (1997) J. Molec. Biol. 273:927-948)). As used herein, a CDR may refer to CDRs defined by either approach or by a combination of both approaches.

In some examples, a functional variant of mAb7E comprises a V_(H) chain that includes a V_(H) CDR1, V_(H) CDR2, and V_(H) CDR3 at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the corresponding V_(H) CDRs of mAb7E, and a V_(L) chain that includes a V_(L) CDR1, V_(L) CDR2, and V_(L) CDR3 at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the corresponding V_(H) CDRs of mAb7E.

Alternatively, the functional variant of mAb7E comprises a V_(H) chain at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the V_(H) chain (mature or precursor) of mAb7E and a V_(L) chain at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the V_(L) chain (mature of precursor) of mAb7E.

The “percent identity” of two amino acid sequences is determined using the algorithm of Karlin and Altschul Proc. Natl. Acad. Sci. USA 87:2264-68, 1990, modified as in Karlin and Altschul Proc. Natl. Acad. Sci. USA 90:5873-77, 1993. Such an algorithm is incorporated into the NBLAST and XBLAST programs (version 2.0) of Altschul, et al. J. Mol. Biol. 215:403-10, 1990. BLAST protein searches can be performed with the XBLAST program, score=50, wordlength=3 to obtain amino acid sequences homologous to the protein molecules of interest. Where gaps exist between two sequences, Gapped BLAST can be utilized as described in Altschul et al., Nucleic Acids Res. 25(17):3389-3402, 1997. When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., XBLAST and NBLAST) can be used.

In other examples, a functional variant of mAb7E comprises a V_(H) chain that includes up to 5 (e.g., 1, 2, 3, 4, or 5) amino acid residue variations in the V_(H) CDR regions (V_(H) CDR1, CDR2, and/or CDR3) as compared to the V_(H) CDRs of mAb7E, and/or a V_(L) chain that includes up to 5 (e.g., 1, 2, 3, 4, or 5) amino acid residue variations in the V_(L) CDR regions (V_(L) CDR1, CDR2, and/or CDR3) as compared to the V_(H) CDRs of mAb7E.

Functional variants of mAb7E are also disclosed in U.S. Pat. No. 7,611,705 and US2011/0064731, both of which are incorporated by reference herein.

In one example, a functional variant of mAb7E is a humanized antibody derived from mAb7E. Provided below are exemplary humanized mAb7E antibodies HL1 and HL2; see also U.S. patent application Ser. No. 13/477,476:

Amino acid sequence and encoding nucleotide sequence of the V_(H) chain of humanized anti-IL-20 antibodies HL1 and HL2:                 ATG TAC TTG GGA CTG AAC TAT GTT TTC ATC GTT TTT CTC CTG AAT                  M   Y   L   G   L   N   Y   V   F   I   V   F   L   L   N GGT GTC CAG AGT GAA GTG CAG CTT GTG GAG TCT GGA GGA GGC TTG GTG CAG CCT GGA  G   V   Q   S   E   V   Q   L   V   E   S   G   G   G   L   V   Q   P   G GGA TCC CTG AAA CTC TCT TGT GCT GCC TCT GGA TTC ACT TTT AGT 

 G   S   L   K   L   S   C   A   A   S   G   F   T   F   S   

 TGG GTC CGC CAG GCT TCC GGG AAG GGG CTT GAG TGG ATT GCT 

      W   V   R   Q   A   S   G   K   G   L   E   W   I   A   

 AGG TTC ACC ATC                                                              R   F   T   I TCA AGA GAT GAT TCC AAA AAC ACC GCC TAC CTG CAA ATG AAC AGC TTA AAA ACC GAG  S   R   D   D   S   K   N   T   A   Y   L   Q   M   N   S   L   K   T   E GAC ACT GCC GTT TAT TAC TGT ACC AAG 

 D   T   A   V   Y   Y   C   T   K    TGG GGC CAG GGG ACC CTG GTC ACC GTC TCC TCA (SEQ ID NO: 5)  W   G   Q   G   T   L   V   T   V   S   S (SEQ ID NO: 6)

The underlined region refers to the signal peptide and the boldfaced/italic regions are the CDRs. SEQ ID NOs: 8 and 7 represent the mature V_(H) amino acid sequence (lacking the signal peptide) and its encoding nucleotide sequence, respectively.

Amino acid sequence and encoding nucleotide sequence of the  V_(L) chain (VL2) of ahumanized anti-IL-20 antibody HL2:             ATG ATG AGT CCT GCC CAG TTC CTG TTT CTG TTG GTG CTC TGG ATT              M   M   S   P   A   Q   F   L   F   L   L   V   L   W   I CGG GAA ACC AAC GGT GAT 

 GTG ATG ACC CAG ACT CCA CTC TCT TTG TCC GTT  R   E   T   N   G   D        V   M   T   Q   T   P   L   S   L   S   V ACC CCT GGA CAA CCA GCC TCC ATC TCT TGC 

 T   P   G   Q   P   A   S   I   S   C   

 TGG TTG TTA CAG AAG CCA GGC CAG TCT CCA                                  W   L   L   Q   K   P   G   Q   S   P CAG CAC CTC ATC TAT 

 GGA GTC CCT GAC AGG TTC  Q   H   L   I   Y                               G   V   P   D   R   F  AGT GGC AGT GGA TCA GGG ACC GAT TTC ACA CTG AAA ATC AGC AGA GTG GAG GCT  S   G   S   G   S   G   T   D   F   T   L   K   I   S   R   V   E   A GAG GAT GTT GGA GTT TAT TAT TGC 

 TTC  E   D   V   G   V   Y   Y   C                                       F GGT GGA GGC ACC AAG GTG GAA ATC AAA (SEQ ID NO: 9)  G   G   G   T   K   V   E   I   K (SEQ ID NO: 10)

The underlined region refers to the signal peptide and the boldfaced/italic regions are the CDRs. SEQ ID NOs: 12 and 11 represent the mature V_(L) amino acid sequence (lacking the signal peptide) and its encoding nucleotide sequence, respectively.

Humanized antibody HL1 comprises the same V_(H) chain as HL2 and a V_(L) chain (SEQ ID NO:13; mature form) that is otherwise identical to the V_(L) of HL2 except that the I residue at position 2 of mature V_(L) of HL2 is replaced with F.

Also disclosed herein are functional variants of the above-noted humanized antibodies HL1 and HL2. Such functional variants can comprise a V_(H) chain that comprises an amino acid sequence at least 85% (e.g., 90%, 92%, 94%, 95%, 96%, 97%, 98%, or 99%) identical to that of the V_(H) of HL1 and HL2 (precursor or mature form; SEQ ID NO:6 and SEQ ID NO:8, respectively) and a V_(L) chain that has an amino acid sequence at least 85% (e.g., 90%, 92%, 94%, 95%, 96%, 97%, 98%, or 99%) identical to that of the V_(L) of HL2 (precursor or mature form; SEQ ID NO:10 and SEQ ID NO:12, respectively). These variants are capable of binding to an IL-20 molecule, particularly a human IL-20 molecule. In some examples, the variants possess similar antigen-binding affinity relative to the exemplary humanized antibody described above (e.g., having a K_(d)<4×10⁻⁹).

(b) Anti-IL-20R Antibodies

An anti-IL-20R antibody is an antibody capable of binding to an IL-20R (e.g., binding to either one of its two subunits or binding to the dimeric complex) and inhibits the biological activity of the IL-20R and/or its downstream pathway(s) mediated by IL-20. In some examples, an anti-IL-20 antibody used in the methods described herein suppresses the IL-20 signaling pathway by at least 20%, at least 40%, at least 50%, at least 75%, at least 90%, at least 100%, or by at least 2-fold, at least 5-fold, at least 10-fold, at least 20-fold, at least 50-fold, at least 100-fold, or at least 1000-fold. In some examples, the anti-IL-20R antibody specifically binds IL-20R1, such as human IL-20R1. Such an antibody may have low affinity to IL-20R2 or the IL-20R1/IL-20R2 complex or does not bind IL-20R2 or the IL-20R1/IL-20R2 complex. In other examples, the anti-IL-20R antibody specifically binds IL-20R2, such as human IL-20R2. Such an antibody may have low affinity to IL-20R1 or the IL-20R1/IL-20R2 complex or does not bind IL-20R1 or the IL-20R1/IL-20R2 complex. In yet other examples, the anti-IL-20R antibody described herein specifically binds the IL-20R1/IL-20R2 complex.

The binding affinity of an anti-IL-20R antibody to IL-20R or a subunit thereof (such as human IL-20R or human IL-20R1) can be less than any of about 100 nM, about 50 nM, about 10 nM, about 1 nM, about 500 pM, about 100 pM, or about 50 pM to any of about 2 pM. Binding affinity can be expressed K_(D) or dissociation constant, and an increased binding affinity corresponds to a decreased K_(D). One way of determining binding affinity of antibodies to IL-20R is by measuring binding affinity of monofunctional Fab fragments of the antibody. To obtain monofunctional Fab fragments, an antibody (for example, IgG) can be cleaved with papain or expressed recombinantly. The affinity of an anti-IL-20R Fab fragment of an antibody can be determined by surface plasmon resonance (BIAcore3000™ surface plasmon resonance (SPR) system, BIAcore, INC, Piscaway N.J.). Kinetic association rates (k_(on)) and dissociation rates (k_(off)) (generally measured at 25° C.) are obtained; and equilibrium dissociation constant (K_(D)) values are calculated as k_(off)/k_(on).

In some embodiments, the antibody binds human IL-20R or a subunit thereof (e.g., human IL-20R1), and does not significantly bind an IL-20R from another mammalian species. In some embodiments, the antibody binds human IL-20R as well as one or more IL-20R from another mammalian species. In still other embodiments, the antibody binds IL-20R and does not significantly cross-react with other cytokine receptors. The epitope(s) bound by the antibody can be continuous or discontinuous.

In some embodiments, the antibody used in the methods described herein is an antibody having the same heavy chain and light chain variable regions (V_(H) and V_(L)) as those of monoclonal antibody mAb7GW or mAb51D, the monoclonal antibodies, an antigen-binding fragment thereof, or a functional equivalent of either mAb7GW or mAb51D. US2011/0256093, which is herein incorporated by reference in its entirety. Shown below are the amino acid sequences of the heavy chains and light chains of mAb7GW and mAb51D, as well as their encoding nucleotide sequences.

Heavy Chain of mAb7GW: Amino Acid Sequence (SEQ ID NO: 14) M R V L I L L W L F T A F P G I L S V V Q L Q E S G P G L V K P S        Signal peptide Q S L S L T C T V T G Y S I T  S D Y A W N  W I R Q F P G N R L E W M  G Y I D Y S G S T K Y N P     CDR1                                          CDR2 S L K S  R I S V T R D T S K N Q F F L Q L N S V T T E D T A T Y Y C A R  D F G D A Y  W G                            CDR3 Q G T L V T V S A A K T T P P S V Y P L A P G S A A Q T N S M V T L G C L V K G Y F P E  P V T V T W N S G S L S S G V H T F P A V L Q S D L Y T L S S S V T V P S S T W P S E T V T C N V A H P A S S T K V D K K I V P R D C G C K P C I C T V P E V S S V F I F P P K P K D V L T I T L T P  K V T C V V V D I S K D D P E V Q F S W F V D D V E V H T A Q T Q P R E E Q F N S T F R S V S E L P I M H Q D W L N G K E F K C R V N S A A F P A P I E K T I S K T K G R P K A P Q V Y T I P P P K E  Q M A K D K V S L T C M I T D F F P E D I T V E W Q W N G Q P A E N Y K N T Q P I M D T D G S Y F V Y S K L N V Q K S N W E A G N T F T C S V L H E G L H N H H T E K S L S H S P G K (The italic region refers to the heavy chain constant region.) Nucleotide Sequence (SEQ ID NO: 15) ATGAGAGTGCTGATTCTTTTGTGGCTGTTCACAGCCTTTCCTGGTATCCTGTCTGTTGTGCAGC      Signal peptide TTCAGGAGTCGGGACCTGGCCTGGTGAAACCTTCTCAGTCTCTGTCCCTCACCTGCACTGTCA CTGGCTACTCAATCACC AGTGATTATGCCTGGAAC TGGATCCGGCAGTTTCCAGGA                         CDR1 AACAGACTGGAGTGGATGGGC TACATAGACTACAGTGGTAGCACTAAATACAACCCC                                      CDR2 TCTCTCAAAAGT CGAATCTCTGTCACTCGAGACACATCCAAGAACCAGTTCTTCCTGCAGTT GAATTCTGTGACTACTGAGGACACAGCCACATATTACTGTGCAAGA GACTTTGGTG                                                     CDR3 ATGCTTAC TGGGGCCAGGGGACTCTGGTCACTGTCTCTGCAGCCAAAACGACACCCCCATCTG TCTATCCACTGGCCCCTGGATCTGCTGCCCAAACTAACTCCATGGTGACCCTGGGATGCCTGGTCA AGGGCTATTTCCCTGAGCCAGTGACAGTGACCTGGAACTCTGGATCCCTGTCCAGCGGTGTGCAC ACCTTCCCAGCTGTCCTGCAGTCTGACCTCTACACTCTGAGCAGCTCAGTGACTGTCCCCTCCAGC ACCTGGCCCAGCGAGACCGTCACCTGCAACGTTGCCCACCCGGCCAGCAGCACCAAGGTGGACA AGAAAATTGTGCCCAGGGATTGTGGTTGTAAGCCTTGCATATGTACAGTCCCAGAAGTATCATCTGT CTTCATCTTCCCCCCAAAGCCCAAGGATGTGCTCACCATTACTCTGACTCCTAAGGTCACGTGTGTT GTGGTAGACATCAGCAAGGATGATCCCGAGGTCCAGTTCAGCTGGTTTGTAGATGATGTGGAGGT GCACACAGCTCAAACGCAACCCCGGGAGGAGCAGTTCAACAGCACTTTCCGCTCAGTCAGTGAAC TTCCCATCATGCACCAGGACTGGCTCAATGGCAAGGAGTTCAAATGCAGGGTCAACAGTGCAGCTT TCCCTGCCCCCATCGAGAAAACCATCTCCAAAACCAAAGGCAGACCGAAGGCTCCACAGGTGTAC ACCATTCCACCTCCCAAGGAGCAAATGGCCAAGGATAAAGTCAGTCTGACCTGCATGATAACAGAC TTCTTCCCTGAAGACATTACTGTGGAGTGGCAGTGGAATGGGCAGCCAGCGGAGAACTACAAGAA CACTCAGCCCATCATGGACACAGATGGCTCTTACTTCGTCTACAGCAAGCTCAATGTGCAGAAGAG CAACTGGGAGGCAGGAAATACTTTCACCTGCTCTGTGTTACATGAGGGCCTGCACAACCACCATAC TGAGAAGAGCCTCTCCCACTCTCCTGGTAAATGA (The italic region encodes the heavy chain constant region.) Light Chain of mAb7GW: Amino Acid Sequence (SEQ ID NO: 16) M D S Q A Q V L M L L L L W V S G S C G D I V M S Q S P S S L A        Signal peptide V S V G E K V T M S C  K S S Q S L L Y S R N Q K N Y L A  W Y Q L K P G Q S P K L L I Y  W A S           CDR1                                               CDR2 T R E S  G V P D R F T G S G S G T D F T L T I S S V K A E D L A V Y Y C  Q Q Y Y S Y P  L                                                    CDR3 T F G A G T K L E L K R A D A A P T V S I F P P S S E Q L T S G G A S V V C F L N N F Y P  K D I N V K W K I D G S E R Q N G V L N S W T D Q D S K D S T Y S M S S T L T L T K D E Y E R H N S Y T C E A T H K T S T S P I  V K S F N R N E C (The italic region refers to the light chain constant region.) Nucleotide Sequence (SEQ ID NO: 17) ATGGATTCACAGGCCCAGGTTCTTATGTTACTGCTGCTATGGGTATCTGGTTCCTGTGGGGACA           Signal peptide TTGTGATGTCACAGTCTCCATCCTCCCTAGCTGTGTCAGTTGGAGAGAAGGTTACTATGAGCT GC AAGTCCAGTCAGAGCCTTTTATATAGTAGGAATCAAAAGAACTACTTGGCC T                       CDR1 GGTACCAGCTGAAGCCAGGGCAGTCTCCTAAACTGCTGATTTAC TGGGCATCCACTAGG                                                 CDR2 GAATCT GGGGTCCCTGATCGCTTCACAGGCAGTGGATCTGGGACAGATTTCACTCTCACCAT CAGCAGTGTGAAGGCTGAAGACCTGGCAGTTTATTACTGT CAGCAATATTATAGCTA                                                CDR3 TCCG CTCACGTTCGGTGCTGGGACCAAGCTGGAGCTGAAACGGGCTGATGCTGCACCAACTG TATCCATCTTCCCACCATCCAGTGAGCAGTTAACATCTGGAGGTGCCTCAGTCGTGTGCTTCTTGAA CAACTTCTACCCCAAAGACATCAATGTCAAGTGGAAGATTGATGGCAGTGAACGACAAAATGGCGT CCTGAACAGTTGGACTGATCAGGACAGCAAAGACAGCACCTACAGCATGAGCAGCACCCTCACGT TGACCAAGGACGAGTATGAACGACATAACAGCTATACCTGTGAGGCCACTCACAAGACATCAACTT CACCCATTGTCAAGAGCTTCAACAGGAATGAGTGTTAG (The italic region encodes the light chain constant region.) Heavy Chain of mAb51D: Amino Acid Sequence (SEQ ID NO: 18) MNFGLSLIFLALILKGVQCEVQLVEAGGDLVKPGGSLKLSCAASGFSLS NYGMS WVRQTPDK      Signal peptide                              CDR1 RLEWVA SISSGGRFTSYPDSVRG RFTISRDNAKNTLYLQMSGLKSEDTAMYYCAR HDGNG             CDR2                                        CDR3 GDY WGQGTSVTVSSAKTTPPSVYPLAPGSAAQTNSMVTLGCLVKGYFPEPVTVTWNSGSLSSGVHTF PAVLQSDLYTLSSSVTVPSSTWPSETVTCNVAHPASSTKVDKKIVPRDCGCKPCICTVPEVSSVFIFPPKP KDVLTITLTPKVTCVVVDISKDDPEVQFSWFVDDVEVHTAQTQPREEQFNSTFRSVSELPIMHQDWLN GKEFKCRVNSAAFPAPIEKTISKTKGRPKAPQVYTIPPPKEQMAKDKVSLTCMITDFFPEDITVEWQWN GQPAENYKNTQPIMDTDGSYFVYSKLNVQKSNWEAGNTFTCSVLHEGLHNHHTEKSLSHSPGK (The italic region refers to the heavy chain constant region.) Nucleotide Sequence (SEQ ID NO: 19) ATGAACTTCGGGCTCAGCCTGATTTTCCTTGCCCTCATTTTAAAAGGTGTCCAGTGTGAGGTGC          Signal peptide AGCTGGTGGAGGCTGGGGGAGACTTAGTGAAGCCTGGAGGGTCCCTGAAACTCTCCTGTGC GGCCTCTGGATTCAGTTTGAGT AACTATGGCATGTCC TGGGTTCGCCAGACTCCAGA                                CDR1 CAAGAGGCTGGAGTGGGTCGCA AGCATTAGTAGTGGTGGTCGTTTCACCTCCTATCC                                          CDR2 AGACAGTGTGAGGGGG CGATTCACCATCTCCAGAGACAATGCCAAGAACACCCTGTACCT GCAAATGAGCGGTCTGAAGTCTGAGGACACAGCCATGTATTACTGTGCAAGA CACGACGGC AACGGTGGGGACTAC TGGGGTCAAGGAACCTCAGTCACCGTCTCCTCAGCCAAA     CDR3 ACGACACCCCCATCTGTCTATCCACTGGCCCCTGGATCTGCTGCCCAAACTAACTCCATGGTGACC CTGGGATGCCTGGTCAAGGGCTATTTCCCTGAGCCAGTGACAGTGACCTGGAACTCTGGATCCCT GTCCAGCGGTGTGCACACCTTCCCAGCTGTCCTGCAGTCTGACCTCTACACTCTGAGCAGCTCAGT GACTGTCCCCTCCAGCACCTGGCCCAGCGAGACCGTCACCTGCAACGTTGCCCACCCGGCCAGC AGCACCAAGGTGGACAAGAAAATTGTGCCCAGGGATTGTGGTTGTAAGCCTTGCATATGTACAGTC CCAGAAGTATCATCTGTCTTCATCTTCCCCCCAAAGCCCAAGGATGTGCTCACCATTACTCTGACTC CTAAGGTCACGTGTGTTGTGGTAGACATCAGCAAGGATGATCCCGAGGTCCAGTTCAGCTGGTTTG TAGATGATGTGGAGGTGCACACAGCTCAGACGCAACCCCGGGAGGAGCAGTTCAACAGCACTTTC CGCTCAGTCAGTGAACTTCCCATCATGCACCAGGACTGGCTCAATGGCAAGGAGTTCAAATGCAGG GTCAACAGTGCAGCTTTCCCTGCCCCCATCGAGAAAACCATCTCCAAAACCAAAGGCAGACCGAAG GCTCCACAGGTGTACACCATTCCACCTCCCAAGGAGCAGATGGCCAAGGATAAAGTCAGTCTGAC CTGCATGATAACAGACTTCTTCCCTGAAGACATTACTGTGGAGTGGCAGTGGAATGGGCAGCCAGC GGAGAACTACAAGAACACTCAGCCCATCATGGACACAGATGGCTCTTACTTCGTCTACAGCAAGCT CAATGTGCAGAAGAGCAACTGGGAGGCAGGAAATACTTTCACCTGCTCTGTGTTACATGAGGGCCT GCACAACCACCATACTGAGAAGAGCCTCTCCCACTCTCCTGGTAAATGA (The italic region encodes the heavy chain constant region.) Light Chain of mAb51D: Amino Acid Sequence (SEQ ID NO: 20) MDFQVQIFSFLLISASVIMSRGQIVLSQFPAILSASPGEKVTMTC RARSSVSFMH WYQQKPGS     Signal peptide                             CDR1 SPKPWIY ATSNLAS GVPPRFSGSGSGTSYSLTISRVEAEDAATYYC QQWSSNP YTFGGGTKLE        CDR2                                    CDR3 IKRADAAPTVSIFPPSSEQLTSGGASVVCFLNNFYPKDINVKWKIDGSERQNGVLNSWTDQDSKDSTYS MSSTLTLTKDEYERHNSYTCEATHKTSTSPIVKSFNRNEC (The italic region refers to the light chain constant region) Nucleotide Sequence (SEQ ID NO: 21) ATGGATTTTCAAGTGCAGATTTTCAGCTTCCTGCTAATCAGTGCTTCAGTCATAATGTCCA                   Signal peptide GAGGACAAATTGTTCTCTCCCAGTTTCCAGCAATCCTGTCTGCATCTCCAGGGGAGAAGGTC ACAATGACTTGCA GGGCCAGGTCAAGTGTAAGTTTCATGCAC TGGTACCAGCAGAA                         CDR1 GCCAGGATCCTCCCCCAAACCCTGGATTTAT GCCACATCCAACCTGGCTTCT GGAGTCC                                       CDR2 CTCCTCGCTTCAGTGGCAGTGGGTCTGGGACCTCTTACTCTCTCACAATCAGCAGAGTGGAG GCTGAAGATGCTGCCACTTATTACTGC CAGCAGTGGAGTAGTAACCCA TACACGTTC                                      CDR3 GGAGGGGGGACTAAGCTGGAAATAAAACGGGCTGATGCTGCACCAACTGTATCCATCTTCCCA CCATCCAGTGAGCAGTTAACATCTGGAGGTGCCTCAGTCGTGTGCTTCTTGAACAACTTCTACCCC AAAGACATCAATGTCAAGTGGAAGATTGATGGCAGTGAACGACAAAATGGCGTCCTGAACAGTTGG ACTGATCAGGACAGCAAAGACAGCACCTACAGCATGAGCAGCACCCTCACGTTGACCAAGGACGA GTATGAACGACATAACAGCTATACCTGTGAGGCCACTCACAAGACATCAACTTCACCCATTGTCAAG AGCTTCAACAGGAATGAGTGTTAG (The italic region encodes the light chain constant region.)

A functional equivalent of mAb7GW or mAb51D has the same epitope-binding specificity as mAb7GW or mAb51D and exhibits at least 20% (e.g., 30%, 40%, 50%, 60%, 70%, 80%, 90%, or greater) of the activity of neutralizing a signaling pathway mediated by IL-20R1 as relative to mAb7GW or mAb51D. In some embodiments, a functional equivalent of mAb7GW or mAb51D contains the same regions/residues responsible for antigen-binding as mAb7GW or mAb51D, such as the same specificity-determining residues in the CDRs or the whole CDRs. The regions/residues that are responsible for antigen-binding can be identified from amino acid sequences of the heavy chain/light chain sequences of mAb7GW or mAb51D (shown above) by methods known in the art. See, e.g., www.bioinf.org.uk/abs; Almagro, J. Mol. Recognit. 17:132-143 (2004); and Chothia et al., J. Mol. Biol. 227:799-817 (1987).

In some examples, a functional equivalent (variant) of mAb7GW or mAb51D comprises a V_(H) chain that includes a V_(H) CDR1, V_(H) CDR2, and V_(H) CDR3 at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the corresponding V_(H) CDRs of mAb7GW or mAb51D, and a V_(L) chain that includes a V_(L) CDR1, V_(L) CDR2, and V_(L) CDR3 at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the corresponding V_(H) CDRs of mAb7GW or mAb51D.

Alternatively, the functional equivalent of mAb7GW or mAb51D comprises a V_(H) chain at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the V_(H) chain (mature or precursor) of mAb7GW or mAb51D and a V_(L) chain at least 75% (e.g., 80%, 85%, 90%, 95%, or 98%) identical to the V_(L) chain (mature of precursor) of mAb7GW or mAb51D.

In other examples, a functional equivalent of mAb7GW or mAb51D comprises a V_(H) chain that includes up to 5 (e.g., 1, 2, 3, 4, or 5) amino acid residue variations in the V_(H) CDR regions (V_(H) CDR1, CDR2, and/or CDR3) as compared to the V_(H) CDRs of mAb7GW or mAb51D, and/or a V_(L) chain that includes up to 5 (e.g., 1, 2, 3, 4, or 5) amino acid residue variations in the V_(L) CDR regions (V_(L) CDR1, CDR2, and/or CDR3) as compared to the V_(H) CDRs of mAb7GW or mAb51D.

(c) Antibody Preparation

Antibodies capable of interfering with the IL-20 signaling pathway as described herein can be made by any method known in the art. See, for example, Harlow and Lane, (1988) Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, New York.

In some embodiments, antibodies specific to a target antigen (e.g., human IL-20 or IL-20R1) can be made by the conventional hybridoma technology. The full-length target antigen or a fragment thereof, optionally coupled to a carrier protein such as KLH, can be used to immunize a host animal for generating antibodies binding to that antigen. The route and schedule of immunization of the host animal are generally in keeping with established and conventional techniques for antibody stimulation and production, as further described herein. General techniques for production of mouse, humanized, and human antibodies are known in the art and are described herein. It is contemplated that any mammalian subject including humans or antibody producing cells therefrom can be manipulated to serve as the basis for production of mammalian, including human hybridoma cell lines. Typically, the host animal is inoculated intraperitoneally, intramuscularly, orally, subcutaneously, intraplantar, and/or intradermally with an amount of immunogen, including as described herein.

Hybridomas can be prepared from the lymphocytes and immortalized myeloma cells using the general somatic cell hybridization technique of Kohler, B. and Milstein, C. (1975) Nature 256:495-497 or as modified by Buck, D. W., et al., In Vitro, 18:377-381 (1982). Available myeloma lines, including but not limited to X63-Ag8.653 and those from the Salk Institute, Cell Distribution Center, San Diego, Calif., USA, may be used in the hybridization. Generally, the technique involves fusing myeloma cells and lymphoid cells using a fusogen such as polyethylene glycol, or by electrical means well known to those skilled in the art. After the fusion, the cells are separated from the fusion medium and grown in a selective growth medium, such as hypoxanthine-aminopterin-thymidine (HAT) medium, to eliminate unhybridized parent cells. Any of the media described herein, supplemented with or without serum, can be used for culturing hybridomas that secrete monoclonal antibodies. As another alternative to the cell fusion technique, EBV immortalized B cells may be used to produce the anti-IL-20 monoclonal antibodies of the subject invention. The hybridomas are expanded and subcloned, if desired, and supernatants are assayed for anti-immunogen activity by conventional immunoassay procedures (e.g., radioimmunoassay, enzyme immunoassay, or fluorescence immunoassay).

Hybridomas that may be used as source of antibodies encompass all derivatives, progeny cells of the parent hybridomas that produce monoclonal antibodies capable of interfering with the IL-20 signaling pathway. Hybridomas that produce such antibodies may be grown in vitro or in vivo using known procedures. The monoclonal antibodies may be isolated from the culture media or body fluids, by conventional immunoglobulin purification procedures such as ammonium sulfate precipitation, gel electrophoresis, dialysis, chromatography, and ultrafiltration, if desired. Undesired activity if present, can be removed, for example, by running the preparation over adsorbents made of the immunogen attached to a solid phase and eluting or releasing the desired antibodies off the immunogen. Immunization of a host animal with a target antigen or a fragment containing the target amino acid sequence conjugated to a protein that is immunogenic in the species to be immunized, e.g., keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin, or soybean trypsin inhibitor using a bifunctional or derivatizing agent, for example maleimidobenzoyl sulfosuccinimide ester (conjugation through cysteine residues), N-hydroxysuccinimide (through lysine residues), glutaraldehyde, succinic anhydride, SOCl, or R1N═C═NR, where R and R1 are different alkyl groups, can yield a population of antibodies (e.g., monoclonal antibodies).

If desired, an antibody (monoclonal or polyclonal) of interest (e.g., produced by a hybridoma) may be sequenced and the polynucleotide sequence may then be cloned into a vector for expression or propagation. The sequence encoding the antibody of interest may be maintained in vector in a host cell and the host cell can then be expanded and frozen for future use. In an alternative, the polynucleotide sequence may be used for genetic manipulation to “humanize” the antibody or to improve the affinity (affinity maturation), or other characteristics of the antibody. For example, the constant region may be engineered to more resemble human constant regions to avoid immune response if the antibody is used in clinical trials and treatments in humans. It may be desirable to genetically manipulate the antibody sequence to obtain greater affinity to the target antigen and greater efficacy in inhibiting the signaling pathway mediated by IL-20. It will be apparent to one of skill in the art that one or more polynucleotide changes can be made to the antibody and still maintain its binding specificity to the target antigen.

In other embodiments, fully human antibodies can be obtained by using commercially available mice that have been engineered to express specific human immunoglobulin proteins. Transgenic animals that are designed to produce a more desirable (e.g., fully human antibodies) or more robust immune response may also be used for generation of humanized or human antibodies. Examples of such technology are Xenomouse® from Amgen, Inc. (Fremont, Calif.) and HuMAb-Mouse® and TC Mouse™ from Medarex, Inc. (Princeton, N.J.). In another alternative, antibodies may be made recombinantly by phage display technology. See, for example, U.S. Pat. Nos. 5,565,332; 5,580,717; 5,733,743; and 6,265,150; and Winter et al., (1994) Annu. Rev. Immunol. 12:433-455. Alternatively, the phage display technology (McCafferty et al., (1990) Nature 348:552-553) can be used to produce human antibodies and antibody fragments in vitro, from immunoglobulin variable (V) domain gene repertoires from unimmunized donors.

Antigen-binding fragments of an intact antibody (full-length antibody) can be prepared via routine methods. For example, F(ab′)2 fragments can be produced by pepsin digestion of an antibody molecule, and Fab fragments that can be generated by reducing the disulfide bridges of F(ab′)2 fragments.

Genetically engineered antibodies, such as humanized antibodies, chimeric antibodies, single-chain antibodies, and bi-specific antibodies, can be produced via, e.g., conventional recombinant technology. In one example, DNA encoding a monoclonal antibodies specific to a target antigen can be readily isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of the monoclonal antibodies). The hybridoma cells serve as a preferred source of such DNA. Once isolated, the DNA may be placed into one or more expression vectors, which are then transfected into host cells such as E. coli cells, simian COS cells, Chinese hamster ovary (CHO) cells, or myeloma cells that do not otherwise produce immunoglobulin protein, to obtain the synthesis of monoclonal antibodies in the recombinant host cells. See, e.g., PCT Publication No. WO 87/04462. The DNA can then be modified, for example, by substituting the coding sequence for human heavy and light chain constant domains in place of the homologous murine sequences, Morrison et al., (1984) Proc. Nat. Acad. Sci. 81:6851, or by covalently joining to the immunoglobulin coding sequence all or part of the coding sequence for a non-immunoglobulin polypeptide. In that manner, genetically engineered antibodies, such as “chimeric” or “hybrid” antibodies; can be prepared that have the binding specificity of a target antigen.

Techniques developed for the production of “chimeric antibodies” are well known in the art. See, e.g., Morrison et al. (1984) Proc. Natl. Acad. Sci. USA 81, 6851; Neuberger et al. (1984) Nature 312, 604; and Takeda et al. (1984) Nature 314:452.

Methods for constructing humanized antibodies are also well known in the art. See, e.g., Queen et al., Proc. Natl. Acad. Sci. USA, 86:10029-10033 (1989). In one example, variable regions of V_(H) and V_(L) of a parent non-human antibody are subjected to three-dimensional molecular modeling analysis following methods known in the art. Next, framework amino acid residues predicted to be important for the formation of the correct CDR structures are identified using the same molecular modeling analysis. In parallel, human V_(H) and V_(L) chains having amino acid sequences that are homologous to those of the parent non-human antibody are identified from any antibody gene database using the parent V_(H) and V_(L) sequences as search queries. Human V_(H) and V_(L) acceptor genes are then selected.

The CDR regions within the selected human acceptor genes can be replaced with the CDR regions from the parent non-human antibody or functional variants thereof. When necessary, residues within the framework regions of the parent chain that are predicted to be important in interacting with the CDR regions (see above description) can be used to substitute for the corresponding residues in the human acceptor genes.

A single-chain antibody can be prepared via recombinant technology by linking a nucleotide sequence coding for a heavy chain variable region and a nucleotide sequence coding for a light chain variable region. Preferably, a flexible linker is incorporated between the two variable regions. Alternatively, techniques described for the production of single chain antibodies (U.S. Pat. Nos. 4,946,778 and 4,704,692) can be adapted to produce a phage scFv library and scFv clones specific to IL-20R1 or IL-20R2 can be identified from the library following routine procedures. Positive clones can be subjected to further screening to identify those that suppress IL-20 receptor activity.

Antibodies obtained following a method known in the art and described herein can be characterized using methods well known in the art. For example, one method is to identify the epitope to which the antigen binds, or “epitope mapping.” There are many methods known in the art for mapping and characterizing the location of epitopes on proteins, including solving the crystal structure of an antibody-antigen complex, competition assays, gene fragment expression assays, and synthetic peptide-based assays, as described, for example, in Chapter 11 of Harlow and Lane, Using Antibodies, a Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1999. In an additional example, epitope mapping can be used to determine the sequence to which an antibody binds. The epitope can be a linear epitope, i.e., contained in a single stretch of amino acids, or a conformational epitope formed by a three-dimensional interaction of amino acids that may not necessarily be contained in a single stretch (primary structure linear sequence). Peptides of varying lengths (e.g., at least 4-6 amino acids long) can be isolated or synthesized (e.g., recombinantly) and used for binding assays with an antibody. In another example, the epitope to which the antibody binds can be determined in a systematic screening by using overlapping peptides derived from the target antigen sequence and determining binding by the antibody. According to the gene fragment expression assays, the open reading frame encoding the target antigen is fragmented either randomly or by specific genetic constructions and the reactivity of the expressed fragments of the antigen with the antibody to be tested is determined. The gene fragments may, for example, be produced by PCR and then transcribed and translated into protein in vitro, in the presence of radioactive amino acids. The binding of the antibody to the radioactively labeled antigen fragments is then determined by immunoprecipitation and gel electrophoresis. Certain epitopes can also be identified by using large libraries of random peptide sequences displayed on the surface of phage particles (phage libraries). Alternatively, a defined library of overlapping peptide fragments can be tested for binding to the test antibody in simple binding assays. In an additional example, mutagenesis of an antigen binding domain, domain swapping experiments and alanine scanning mutagenesis can be performed to identify residues required, sufficient, and/or necessary for epitope binding. For example, domain swapping experiments can be performed using a mutant of a target antigen in which various fragments of the IL-20 polypeptide have been replaced (swapped) with sequences from a closely related, but antigenically distinct protein (such as another member of the neurotrophin protein family). By assessing binding of the antibody to the mutant IL-20, the importance of the particular antigen fragment to antibody binding can be assessed.

Alternatively, competition assays can be performed using other antibodies known to bind to the same antigen to determine whether an antibody binds to the same epitope as the other antibodies. Competition assays are well known to those of skill in the art.

Other IL-20 Antagonists

IL-20 antagonists other than antibodies capable of interfering with the IL-20 signaling pathway as described above can be used in the methods described herein.

In some embodiments of the invention, the IL-20 antagonist comprises at least one antisense nucleic acid molecule capable of blocking or decreasing the expression of a functional IL-20 (e.g., a human IL-20) or a subunit of an IL-20 receptor (e.g., IL-20R1). Nucleotide sequences of the IL-20 and IL-20 receptor subunits are known and are readily available from publicly available databases. See above disclosures. It is routine to prepare antisense oligonucleotide molecules that will specifically bind a target mRNA without cross-reacting with other polynucleotides. Exemplary sites of targeting include, but are not limited to, the initiation codon, the 5′ regulatory regions, the coding sequence and the 3′ untranslated region. In some embodiments, the oligonucleotides are about 10 to 100 nucleotides in length, about 15 to 50 nucleotides in length, about 18 to 25 nucleotides in length, or more. The oligonucleotides can comprise backbone modifications such as, for example, phosphorothioate linkages, and 2′-0 sugar modifications well known in the art.

Alternatively, IL-20/IL-20R expression and/or release can be decreased using gene knockdown, morpholino oligonucleotides, small interfering RNA (siRNA or RNAi), microRNA or ribozymes, methods that are well-known in the art. RNA interference (RNAi) is a process in which a dsRNA directs homologous sequence-specific degradation of messenger RNA. In mammalian cells, RNAi can be triggered by 21-nucleotide duplexes of small interfering RNA (siRNA) without activating the host interferon response. The dsRNA used in the methods disclosed herein can be a siRNA (containing two separate and complementary RNA chains) or a short hairpin RNA (i.e., a RNA chain forming a tight hairpin structure), both of which can be designed based on the sequence of the target gene. Alternatively, it can be a microRNA.

Optionally, a nucleic acid molecule to be used in the method described herein (e.g., an antisense nucleic acid, a small interfering RNA, or a microRNA) as described above contains non-naturally-occurring nucleobases, sugars, or covalent internucleoside linkages (backbones). Such a modified oligonucleotide confers desirable properties such as enhanced cellular uptake, improved affinity to the target nucleic acid, and increased in vivo stability.

In one example, the nucleic acid has a modified backbone, including those that retain a phosphorus atom (see, e.g., U.S. Pat. Nos. 3,687,808; 4,469,863; 5,321,131; 5,399,676; and 5,625,050) and those that do not have a phosphorus atom (see, e.g., U.S. Pat. Nos. 5,034,506; 5,166,315; and 5,792,608). Examples of phosphorus-containing modified backbones include, but are not limited to, phosphorothioates, chiral phosphorothioates, phosphorodithioates, phosphotriesters, aminoalkyl-phosphotriesters, methyl and other alkyl phosphonates including 3′-alkylene phosphonates, 5′-alkylene phosphonates and chiral phosphonates, phosphinates, phosphoramidates including 3′-amino phosphoramidate and aminoalkylphosphoramidates, thionophosphoramidates, thionoalkylphosphonates, thionoalkylphosphotriesters, selenophosphates and boranophosphates having 3′-5′ linkages, or 2′-5′ linkages. Such backbones also include those having inverted polarity, i.e., 3′ to 3′, 5′ to 5′ or 2′ to 2′ linkage. Modified backbones that do not include a phosphorus atom are formed by short chain alkyl or cycloalkyl internucleoside linkages, mixed heteroatom and alkyl or cycloalkyl internucleoside linkages, or one or more short chain heteroatomic or heterocyclic internucleoside linkages. Such backbones include those having morpholino linkages (formed in part from the sugar portion of a nucleoside); siloxane backbones; sulfide, sulfoxide and sulfone backbones; formacetyl and thioformacetyl backbones; methylene formacetyl and thioformacetyl backbones; riboacetyl backbones; alkene containing backbones; sulfamate backbones; methyleneimino and methylenehydrazino backbones; sulfonate and sulfonamide backbones; amide backbones; and others having mixed N, O, S and CH₂ component parts.

In another example, the nucleic acid used in the disclosed methods includes one or more substituted sugar moieties. Such substituted sugar moieties can include one of the following groups at their 2′ position: OH; F; O-alkyl, S-alkyl, N-alkyl, O-alkenyl, S-alkenyl, N-alkenyl; O-alkynyl, S-alkynyl, N-alkynyl, and O-alkyl-O-alkyl. In these groups, the alkyl, alkenyl and alkynyl can be substituted or unsubstituted C₁ to C₁₀ alkyl or C₂ to C₁₀ alkenyl and alkynyl. They may also include at their 2′ position heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalkylamino, substituted silyl, an RNA cleaving group, a reporter group, an intercalator, a group for improving the pharmacokinetic properties of an oligonucleotide, or a group for improving the pharmacodynamic properties of an oligonucleotide. Preferred substituted sugar moieties include those having 2′-methoxyethoxy, 2′-dimethylaminooxyethoxy, and 2′-dimethylaminoethoxyethoxy. See Martin et al., Helv. Chim. Acta, 1995, 78, 486-504.

In yet another example, the nucleic acid includes one or more modified native nucleobases (i.e., adenine, guanine, thymine, cytosine and uracil). Modified nucleobases include those described in U.S. Pat. No. 3,687,808, The Concise Encyclopedia Of Polymer Science And Engineering, pages 858-859, Kroschwitz, J. I., ed. John Wiley & Sons, 1990, Englisch et al., Angewandte Chemie, International Edition, 1991, 30, 613, and Sanghvi, Y. S., Chapter 15, Antisense Research and Applications, pages 289-302, CRC Press, 1993. Certain of these nucleobases are particularly useful for increasing the binding affinity of the antisense oligonucleotide to its target nucleic acid. These include 5-substituted pyrimidines, 6-azapyrimidines and N-2, N-6 and 0-6 substituted purines (e.g., 2-aminopropyl-adenine, 5-propynyluracil and 5-propynylcytosine). See Sanghvi, et al., eds., Antisense Research and Applications, CRC Press, Boca Raton, 1993, pp. 276-278).

Any of the nucleic acids can be synthesized by methods known in the art. See, e.g., Caruthers et al., 1992, Methods in Enzymology 211, 3-19, Wincott et al., 1995, Nucleic Acids Res. 23, 2677-2684, Wincott et al., 1997, Methods Mol. Bio. 74, 59, Brennan et al., 1998, Biotechnol Bioeng., 61, 33-45, and Brennan, U.S. Pat. No. 6,001,311. It can also be transcribed from an expression vector and isolated using standard techniques.

In other embodiments, the IL-20 antagonist comprises at least one IL-20 or IL-20R inhibitory compound. As used herein, “IL-20 inhibitory compound” or “IL-20R inhibitory compound” refers to a compound other than an anti-IL-20 or anti-IL-20R antibody that directly or indirectly reduces, inhibits, neutralizes, or abolishes IL-20/IL-20R biological activity. An IL-20/IL-20R inhibitory compound should exhibit any one or more of the following characteristics: (a) binds to IL-20 or IL-20R and inhibits its biological activity and/or downstream pathways mediated by IL-20 signaling function; (b) prevents, ameliorates, or treats any aspect of liver fibrosis/cirrhosis; (c) blocks or decreases IL-20 receptor activation; (d) increases clearance of IL-20 or IL-20R; (e) inhibits (reduces) IL-20 or IL-20R synthesis, production or release. One skilled in the art can prepare other small molecules inhibitory compounds.

In some embodiments, an IL-20 or IL-20R inhibitory compound is an IL-20 mutant, an IL-19 mutant, or an IL-24 mutant, which can bind to an IL-20 receptor but cannot elicit signal transduction. Such a mutant may block binding of wild type IL-20 to an IL-20 receptor thus preventing IL-20 signal transduction.

In other embodiments, the IL-20 or IL-20R inhibitory compounds described herein are small molecules, which can have a molecular weight of about any of 100 to 20,000 daltons, 500 to 15,000 daltons, or 1000 to 10,000 daltons. Libraries of small molecules are commercially available. The small molecules can be administered using any means known in the art, including inhalation, intraperitoneally, intravenously, intramuscularly, subcutaneously, intrathecally, intraventricularly, orally, enterally, parenterally, intranasally, or dermally. In general, when the IL-20-antagonist according to the invention is a small molecule, it will be administered at the rate of 0.1 to 300 mg/kg of the weight of the patient divided into one to three or more doses. For an adult patient of normal weight, doses ranging from 1 mg to 5 g per dose can be administered.

The above-mentioned small molecules can be obtained from compound libraries. The libraries can be spatially addressable parallel solid phase or solution phase libraries. See, e.g., Zuckermann et al. J. Med. Chem. 37, 2678-2685, 1994; and Lam Anticancer Drug Des. 12:145, 1997. Methods for the synthesis of compound libraries are well known in the art, e.g., DeWitt et al. PNAS USA 90:6909, 1993; Erb et al. PNAS USA 91:11422, 1994; Zuckermann et al. J. Med. Chem. 37:2678, 1994; Cho et al. Science 261:1303, 1993; Carrell et al. Angew Chem. Int. Ed. Engl. 33:2059, 1994; Carell et al. Angew Chem. Int. Ed. Engl. 33:2061, 1994; and Gallop et al. J. Med. Chem. 37:1233, 1994. Libraries of compounds may be presented in solution (e.g., Houghten Biotechniques 13:412-421, 1992), or on beads (Lam Nature 354:82-84, 1991), chips (Fodor Nature 364:555-556, 1993), bacteria (U.S. Pat. No. 5,223,409), spores (U.S. Pat. No. 5,223,409), plasmids (Cull et al. PNAS USA 89:1865-1869, 1992), or phages (Scott and Smith Science 249:386-390, 1990; Devlin Science 249:404-406, 1990; Cwirla et al. PNAS USA 87:6378-6382, 1990; Felici J. Mol. Biol. 222:301-310, 1991; and U.S. Pat. No. 5,223,409).

In other embodiments, the IL-20 antagonists can be a polypeptide comprising an extracellular portion of an IL-20 receptor (such as IL-20 R1, IL-20R2, or IL-22R1), wherein the polypeptide specifically binds to 11-20 and blocks its interaction with one or more IL-20 receptors. In some embodiments, the extracellular portion of the IL-20 receptor is fused to a Fc domain of antibody. Examples of the soluble receptors are described in PCT WO 01/46232.

Identification of IL-20 Antagonists

IL-20 antagonists can be identified or characterized using methods known in the art, whereby reduction, amelioration, or neutralization of an IL-20 biological activity is detected and/or measured. For example, an ELISA-type assay may be suitable for qualitative or quantitative measurement of IL-20 mediated kinase activation by measuring the phosphorylation of proteins activated through an IL-20 cascade. Examples include JNK, ERK, AKT, p38, STAT3 and TRAF6.

The IL-20 antagonists can also be identified by incubating a candidate agent with IL-20 or IL-20R and monitoring any one or more of the following characteristics: (a) binding to IL-20 or IL-20R and inhibiting its biological activity and/or downstream pathways mediated by IL-20 signaling function; (b) preventing, ameliorating, or treating any aspect of liver fibrosis/cirrhosis; (c) blocking or decreasing IL-20 receptor activation; (d) increasing clearance of IL-20 or IL-20R; (e) inhibiting (reducing) IL-20 synthesis, production or release. In some embodiments, an IL-20 antagonist is identified by incubating a candidate agent with IL-20 or IL-20R and monitoring binding and attendant reduction or neutralization of a biological activity of IL-20 or IL-20R. The binding assay may be performed with purified IL-20 or IL-20R polypeptide(s), or with cells naturally expressing, or transfected to express, IL-20 or IL-20R polypeptide(s). In one embodiment, the binding assay is a competitive binding assay, where the ability of a candidate antibody to compete with a known IL-20 antagonist for IL-20 or IL-20R binding is evaluated. The assay may be performed in various formats, including the ELISA format. In other embodiments, an IL-20 antagonist is identified by incubating a candidate agent with IL-20 or IL-20R (e.g., IL-20R1) and monitoring attendant inhibition of IL-20R1/IL-20R2 complex formation or IL-20R2/IL-22R1 complex formation. Following initial identification, the activity of a candidate IL-20 antagonist can be further confirmed and refined by bioassays, known to test the targeted biological activities. Alternatively, bioassays can be used to screen candidates directly.

The examples provided below provide a number of assays that can be used to screen candidate IL-20 antagonists. Bioassays include but are not limited to flow cytometry of determine competitive binding of IL-20 to cells in the presence of candidate IL-20 antagonists; and inhibition of IL-20-induced apoptosis in renal epithelial cells. In addition, RT-PCR or Real-time PCR which can be used to directly measure IL-20 expression or to measure expression of genes upregulated by IL-20 such as TNFα MCP-1, IL-1β, IL-6 and VEGF.

Pharmaceutical Compositions

One or more of the above-described IL-20 antagonist can be mixed with a pharmaceutically acceptable carrier (excipient), including buffer, to form a pharmaceutical composition for use in alleviating liver fibrosis/cirrhosis. “Acceptable” means that the carrier must be compatible with the active ingredient of the composition (and preferably, capable of stabilizing the active ingredient) and not deleterious to the subject to be treated. Pharmaceutically acceptable excipients (carriers) including buffers, which are well known in the art. See, e.g., Remington: The Science and Practice of Pharmacy 20th Ed. (2000) Lippincott Williams and Wilkins, Ed. K. E. Hoover. In one example, a pharmaceutical composition described herein contains more than one anti-IL-20 or anti-IL-20R antibodies that recognize different epitopes of the target antigen. In another example, the pharmaceutical composition comprises at least two different-typed IL-20 antagonists (e.g., one antibody and one small molecule).

The pharmaceutical compositions to be used in the present methods can comprise pharmaceutically acceptable carriers, excipients, or stabilizers in the form of lyophilized formulations or aqueous solutions. (Remington: The Science and Practice of Pharmacy 20th Ed. (2000) Lippincott Williams and Wilkins, Ed. K. E. Hoover). Acceptable carriers, excipients, or stabilizers are nontoxic to recipients at the dosages and concentrations used, and may comprise buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride, benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrans; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counter-ions such as sodium; metal complexes (e.g. Zn-protein complexes); and/or non-ionic surfactants such as TWEEN™, PLURONICS™ or polyethylene glycol (PEG). Pharmaceutically acceptable excipients are further described herein.

In some examples, the pharmaceutical composition described herein comprises liposomes containing the IL-20 antagonist (such as an antibody), which can be prepared by methods known in the art, such as described in Epstein, et al., Proc. Natl. Acad. Sci. USA 82:3688 (1985); Hwang, et al., Proc. Natl. Acad. Sci. USA 77:4030 (1980); and U.S. Pat. Nos. 4,485,045 and 4,544,545. Liposomes with enhanced circulation time are disclosed in U.S. Pat. No. 5,013,556. Particularly useful liposomes can be generated by the reverse phase evaporation method with a lipid composition comprising phosphatidylcholine, cholesterol and PEG-derivatized phosphatidylethanolamine (PEG-PE). Liposomes are extruded through filters of defined pore size to yield liposomes with the desired diameter.

The active ingredients (e.g., an IL-20 antagonist) may also be entrapped in microcapsules prepared, for example, by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethacylate) microcapsules, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions. Such techniques are known in the art, see, e.g., Remington, The Science and Practice of Pharmacy 20th Ed. Mack Publishing (2000).

In other examples, the pharmaceutical composition described herein can be formulated in sustained-release format. Suitable examples of sustained-release preparations include semipermeable matrices of solid hydrophobic polymers containing the antibody, which matrices are in the form of shaped articles, e.g. films, or microcapsules. Examples of sustained-release matrices include polyesters, hydrogels (for example, poly(2-hydroxyethyl-methacrylate), or poly(v nylalcohol)), polylactides (U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and 7 ethyl-L-glutamate, non-degradable ethylene-vinyl acetate, degradable lactic acid-glycolic acid copolymers such as the LUPRON DEPOT™ (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate), sucrose acetate isobutyrate, and poly-D-(−)-3-hydroxybutyric acid.

The pharmaceutical compositions to be used for in vivo administration must be sterile. This is readily accomplished by, for example, filtration through sterile filtration membranes. Therapeutic antibody compositions are generally placed into a container having a sterile access port, for example, an intravenous solution bag or vial having a stopper pierceable by a hypodermic injection needle.

The pharmaceutical compositions described herein can be in unit dosage forms such as tablets, pills, capsules, powders, granules, solutions or suspensions, or suppositories, for oral, parenteral or rectal administration, or administration by inhalation or insufflation.

For preparing solid compositions such as tablets, the principal active ingredient can be mixed with a pharmaceutical carrier, e.g. conventional tableting ingredients such as corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums, and other pharmaceutical diluents, e.g. water, to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a non-toxic pharmaceutically acceptable salt thereof. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules. This solid preformulation composition is then subdivided into unit dosage forms of the type described above containing from 0.1 to about 500 mg of the active ingredient of the present invention. The tablets or pills of the novel composition can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer that serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate.

Suitable surface-active agents include, in particular, non-ionic agents, such as polyoxyethylenesorbitans (e.g. Tween™ 20, 40, 60, 80 or 85) and other sorbitans (e.g. Span™ 20, 40, 60, 80 or 85). Compositions with a surface-active agent will conveniently comprise between 0.05 and 5% surface-active agent, and can be between 0.1 and 2.5%. It will be appreciated that other ingredients may be added, for example mannitol or other pharmaceutically acceptable vehicles, if necessary.

Suitable emulsions may be prepared using commercially available fat emulsions, such as Intralipid™, Liposyn™, Infonutrol™, Lipofundin™ and Lipiphysan™. The active ingredient may be either dissolved in a pre-mixed emulsion composition or alternatively it may be dissolved in an oil (e.g. soybean oil, safflower oil, cottonseed oil, sesame oil, corn oil or almond oil) and an emulsion formed upon mixing with a phospholipid (e.g. egg phospholipids, soybean phospholipids or soybean lecithin) and water. It will be appreciated that other ingredients may be added, for example glycerol or glucose, to adjust the tonicity of the emulsion. Suitable emulsions will typically contain up to 20% oil, for example, between 5 and 20%. The fat emulsion can comprise fat droplets between 0.1 and 1.0 .im, particularly 0.1 and 0.5 .im, and have a pH in the range of 5.5 to 8.0.

The emulsion compositions can be those prepared by mixing an IL-20 antagonist with Intralipid™ or the components thereof (soybean oil, egg phospholipids, glycerol and water).

Pharmaceutical compositions for inhalation or insufflation include solutions and suspensions in pharmaceutically acceptable, aqueous or organic solvents, or mixtures thereof, and powders. The liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as set out above. In some embodiments, the compositions are administered by the oral or nasal respiratory route for local or systemic effect.

Compositions in preferably sterile pharmaceutically acceptable solvents may be nebulised by use of gases. Nebulised solutions may be breathed directly from the nebulising device or the nebulising device may be attached to a face mask, tent or intermittent positive pressure breathing machine. Solution, suspension or powder compositions may be administered, preferably orally or nasally, from devices which deliver the formulation in an appropriate manner.

Use of IL-20 Antagonists for Treating Liver Fibrosis

To practice the method disclosed herein, an effective amount of the pharmaceutical composition described above can be administered to a subject (e.g., a human) in need of the treatment via a suitable route, such as intravenous administration, e.g., as a bolus or by continuous infusion over a period of time, by intramuscular, intraperitoneal, intracerobrospinal, subcutaneous, intra-articular, intrasynovial, intrathecal, oral, inhalation or topical routes. Commercially available nebulizers for liquid formulations, including jet nebulizers and ultrasonic nebulizers are useful for administration. Liquid formulations can be directly nebulized and lyophilized powder can be nebulized after reconstitution. Alternatively, IL-20 antagonists can be aerosolized using a fluorocarbon formulation and a metered dose inhaler, or inhaled as a lyophilized and milled powder.

The subject to be treated by the methods described herein can be a mammal, more preferably a human. Mammals include, but are not limited to, farm animals, sport animals, pets, primates, horses, dogs, cats, mice and rats. A human subject who needs the treatment may be a human patient having, at risk for, or suspected of having liver fibrosis (e.g., liver cirrhosis). A subject having liver fibrosis can be identified by routine medical examination, e.g., laboratory tests, liver functions tests, liver biopsy, CT scans, or ultrasounds. A subject suspected of having liver fibrosis might show one or more symptoms of the disorder, e.g., elevated levels of aminotransferases (AST and ALT), levels of alkaline phosphatase and gamma-glutamyl transferase, elevated levels of bilirubin (a marker for cirrhosis progresses), decreased level of albumin, increased prothrombin time, elevated levels of globulin, leukopenia and neutropenia, and/or coagulation defects. A subject at risk for liver fibrosis can be a subject having one or more of the risk factors for that disorder. For example, risk factors associated with liver fibrosis include (a) viral infection, particularly HBV or HCV infection, (b) age (liver fibrosis is more frequent in people over 50), (c) gender (occur more rapidly in men than in women), (d) heavy alcohol consumption, (e) fatty liver, and (f) insulin resistance.

“An effective amount” as used herein refers to the amount of each active agent required to confer therapeutic effect on the subject, either alone or in combination with one or more other active agents. Effective amounts vary, as recognized by those skilled in the art, depending on the particular condition being treated, the severity of the condition, the individual patient parameters including age, physical condition, size, gender and weight, the duration of the treatment, the nature of concurrent therapy (if any), the specific route of administration and like factors within the knowledge and expertise of the health practitioner. These factors are well known to those of ordinary skill in the art and can be addressed with no more than routine experimentation. It is generally preferred that a maximum dose of the individual components or combinations thereof be used, that is, the highest safe dose according to sound medical judgment. It will be understood by those of ordinary skill in the art, however, that a patient may insist upon a lower dose or tolerable dose for medical reasons, psychological reasons or for virtually any other reasons.

Empirical considerations, such as the half-life, generally will contribute to the determination of the dosage. For example, antibodies that are compatible with the human immune system, such as humanized antibodies or fully human antibodies, may be used to prolong half-life of the antibody and to prevent the antibody being attacked by the host's immune system. Frequency of administration may be determined and adjusted over the course of therapy, and is generally, but not necessarily, based on treatment and/or suppression and/or amelioration and/or delay of liver fibrosis/cirrhosis. Alternatively, sustained continuous release formulations of an IL-20 antagonist may be appropriate. Various formulations and devices for achieving sustained release are known in the art.

In one example, dosages for an IL-20 antagonist as described herein may be determined empirically in individuals who have been given one or more administration(s) of IL-20 antagonist. Individuals are given incremental dosages of the antagonist. To assess efficacy of the antagonist, an indicator of liver fibrosis (such as levels of AST and ALT) can be followed.

Generally, for administration of any of the antibodies described herein, an initial candidate dosage can be about 2 mg/kg. For the purpose of the present disclosure, a typical daily dosage might range from about any of 0.1 μg/kg to 3 μg/kg to 30 μg/kg to 300 μg/kg to 3 mg/kg, to 30 mg/kg to 100 mg/kg or more, depending on the factors mentioned above. For repeated administrations over several days or longer, depending on the condition, the treatment is sustained until a desired suppression of symptoms occurs or until sufficient therapeutic levels are achieved to alleviate liver fibrosis or cirrhosis, or a symptom thereof. An exemplary dosing regimen comprises administering an initial dose of about 2 mg/kg, followed by a weekly maintenance dose of about 1 mg/kg of the antibody, or followed by a maintenance dose of about 1 mg/kg every other week. However, other dosage regimens may be useful, depending on the pattern of pharmacokinetic decay that the practitioner wishes to achieve. For example, dosing from one-four times a week is contemplated. In some embodiments, dosing ranging from about 3 μg/mg to about 2 mg/kg (such as about 3 μg/mg, about 10 μg/mg, about 30 μg/mg, about 100 μg/mg, about 300 μg/mg, about 1 mg/kg, and about 2 mg/kg) may be used. In some embodiments, dosing frequency is once every week, every 2 weeks, every 4 weeks, every 5 weeks, every 6 weeks, every 7 weeks, every 8 weeks, every 9 weeks, or every 10 weeks; or once every month, every 2 months, or every 3 months, or longer. The progress of this therapy is easily monitored by conventional techniques and assays. The dosing regimen (including the antibody used) can vary over time.

When the IL-20 antagonist is not an antibody, it may be administered at the rate of about 0.1 to 300 mg/kg of the weight of the patient divided into one to three doses, or as disclosed herein. In some embodiments, for an adult patient of normal weight, doses ranging from about 0.3 to 5.00 mg/kg may be administered. The particular dosage regimen, i.e., dose, timing and repetition, will depend on the particular individual and that individual's medical history, as well as the properties of the individual agents (such as the half-life of the agent, and other considerations well known in the art).

For the purpose of the present disclosure, the appropriate dosage of an IL-20 antagonist will depend on the specific IL-20 antagonist(s) (or compositions thereof) employed, the type and severity of liver fibrosis/cirrhosis, whether the antagonist is administered for preventive or therapeutic purposes, previous therapy, the patient's clinical history and response to the antagonist, and the discretion of the attending physician. Typically the clinician will administer an IL-20 antagonist, such as an anti-IL-20 or anti-IL-20R antibody, until a dosage is reached that achieves the desired result. Administration of an IL-20 antagonist can be continuous or intermittent, depending, for example, upon the recipient's physiological condition, whether the purpose of the administration is therapeutic or prophylactic, and other factors known to skilled practitioners. The administration of an IL-20 antagonist (for example if the IL-20 antagonist is an anti-IL-20 antibody) may be essentially continuous over a preselected period of time or may be in a series of spaced dose, e.g., either before, during, or after developing liver fibrosis or cirrhosis.

As used herein, the term “treating” refers to the application or administration of a composition including one or more active agents to a subject, who has liver fibrosis, a symptom of liver fibrosis, or a predisposition toward the disease, with the purpose to cure, heal, alleviate, relieve, alter, remedy, ameliorate, improve, or affect the disorder, the symptom of the disease, or the predisposition toward the disease.

Alleviating liver fibrosis or cirrhosis includes delaying the development or progression of the disease, or reducing disease severity. Alleviating the disease does not necessarily require curative results. As used therein, “delaying” the development of a disease (such as liver fibrosis or cirrhosis) means to defer, hinder, slow, retard, stabilize, and/or postpone progression of the disease. This delay can be of varying lengths of time, depending on the history of the disease and/or individuals being treated. A method that “delays” or alleviates the development of a disease, or delays the onset of the disease, is a method that reduces probability of developing one or more symptoms of the disease in a given time frame and/or reduces extent of the symptoms in a given time frame, when compared to not using the method. Such comparisons are typically based on clinical studies, using a number of subjects sufficient to give a statistically significant result.

“Development” or “progression” of a disease means initial manifestations and/or ensuing progression of the disease. Development of the disease can be detectable and assessed using standard clinical techniques as well known in the art. However, development also refers to progression that may be undetectable. For purpose of this disclosure, development or progression refers to the biological course of the symptoms. “Development” includes occurrence, recurrence, and onset. As used herein “onset” or “occurrence” of liver fibrosis includes initial onset and/or recurrence.

In some embodiments, the IL-20 antagonist (e.g., an anti-IL-20 antibody or anti-IL-20R antibody such as anti-IL-20R1 antibody) described herein is administered to a subject in need of the treatment at an amount sufficient to reduce the level of the IL-20 receptor/IL-20-mediated signaling by at least 20% (e.g., 30%, 40%, 50%, 60%, 70%, 80%, 90% or greater). In other embodiments, the antagonist is administered in an amount effective in reducing the enzymatic activity of AST and/ALT in the subject. Alternatively, the antagonist is administered in an amount effective in reversing the activation of HSC cells, which can be induced by IL-20.

Conventional methods, known to those of ordinary skill in the art of medicine, can be used to administer the pharmaceutical composition to the subject, depending upon the type of disease to be treated or the site of the disease. This composition can also be administered via other conventional routes, e.g., administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. The term “parenteral” as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intraarticular, intraarterial, intrasynovial, intrasternal, intrathecal, intralesional, and intracranial injection or infusion techniques. In addition, it can be administered to the subject via injectable depot routes of administration such as using 1-, 3-, or 6-month depot injectable or biodegradable materials and methods.

Injectable compositions may contain various carriers such as vegetable oils, dimethylactamide, dimethyformamide, ethyl lactate, ethyl carbonate, isopropyl myristate, ethanol, and polyols (glycerol, propylene glycol, liquid polyethylene glycol, and the like). For intravenous injection, water soluble antibodies can be administered by the drip method, whereby a pharmaceutical formulation containing the antibody and a physiologically acceptable excipients is infused. Physiologically acceptable excipients may include, for example, 5% dextrose, 0.9% saline, Ringer's solution or other suitable excipients. Intramuscular preparations, e.g., a sterile formulation of a suitable soluble salt form of the antibody, can be dissolved and administered in a pharmaceutical excipient such as Water-for-Injection, 0.9% saline, or 5% glucose solution.

In one embodiment, an IL-20 antagonist is administered via site-specific or targeted local delivery techniques. Examples of site-specific or targeted local delivery techniques include various implantable depot sources of the IL-20 antagonist or local delivery catheters, such as infusion catheters, an indwelling catheter, or a needle catheter, synthetic grafts, adventitial wraps, shunts and stents or other implantable devices, site specific carriers, direct injection, or direct application. See, e.g., PCT Publication No. WO 00/53211 and U.S. Pat. No. 5,981,568.

Targeted delivery of therapeutic compositions containing an antisense polynucleotide, expression vector, or subgenomic polynucleotides can also be used. Receptor-mediated DNA delivery techniques are described in, for example, Findeis et al., Trends Biotechnol. (1993) 11:202; Chiou et al., Gene Therapeutics: Methods And Applications Of Direct Gene Transfer (J. A. Wolff, ed.) (1994); Wu et al., J. Biol. Chem. (1988) 263:621; Wu et al., J. Biol. Chem. (1994) 269:542; Zenke et al., Proc. Natl. Acad. Sci. USA (1990) 87:3655; Wu et al., J. Biol. Chem. (1991) 266:338. Therapeutic compositions containing a polynucleotide are administered in a range of about 100 ng to about 200 mg of DNA for local administration in a gene therapy protocol. In some embodiments, concentration ranges of about 500 ng to about 50 mg, about 1 μg to about 2 mg, about 5 μg to about 500 μg, and about 20 μg to about 100 μg of DNA or more can also be used during a gene therapy protocol.

The therapeutic polynucleotides and polypeptides described herein can be delivered using gene delivery vehicles. The gene delivery vehicle can be of viral or non-viral origin (see generally, Jolly, Cancer Gene Therapy (1994) 1:51; Kimura, Human Gene Therapy (1994) 5:845; Connelly, Human Gene Therapy (1995) 1:185; and Kaplitt, Nature Genetics (1994) 6:148). Expression of such coding sequences can be induced using endogenous mammalian or heterologous promoters and/or enhancers. Expression of the coding sequence can be either constitutive or regulated.

Viral-based vectors for delivery of a desired polynucleotide and expression in a desired cell are well known in the art. Exemplary viral-based vehicles include, but are not limited to, recombinant retroviruses (see, e.g., PCT Publication Nos. WO 90/07936; WO 94/03622; WO 93/25698; WO 93/25234; WO 93/11230; WO 93/10218; WO 91/02805; U.S. Pat. Nos. 5,219,740 and 4,777,127; GB Patent No. 2,200,651; and EP Patent No. 0 345 242), alphavirus-based vectors (e.g., Sindbis virus vectors, Semliki forest virus (ATCC VR-67; ATCC VR-1247), Ross River virus (ATCC VR-373; ATCC VR-1246) and Venezuelan equine encephalitis virus (ATCC VR-923; ATCC VR-1250; ATCC VR 1249; ATCC VR-532)), and adeno-associated virus (AAV) vectors (see, e.g., PCT Publication Nos. WO 94/12649, WO 93/03769; WO 93/19191; WO 94/28938; WO 95/11984 and WO 95/00655). Administration of DNA linked to killed adenovirus as described in Curiel, Hum. Gene Ther. (1992) 3:147 can also be employed.

Non-viral delivery vehicles and methods can also be employed, including, but not limited to, polycationic condensed DNA linked or unlinked to killed adenovirus alone (see, e.g., Curiel, Hum. Gene Ther. (1992) 3:147); ligand-linked DNA (see, e.g., Wu, J. Biol. Chem. (1989) 264:16985); eukaryotic cell delivery vehicles cells (see, e.g., U.S. Pat. No. 5,814,482; PCT Publication Nos. WO 95/07994; WO 96/17072; WO 95/30763; and WO 97/42338) and nucleic charge neutralization or fusion with cell membranes. Naked DNA can also be employed. Exemplary naked DNA introduction methods are described in PCT Publication No. WO 90/11092 and U.S. Pat. No. 5,580,859. Liposomes that can act as gene delivery vehicles are described in U.S. Pat. No. 5,422,120; PCT Publication Nos. WO 95/13796; WO 94/23697; WO 91/14445; and EP Patent No. 0524968. Additional approaches are described in Philip, Mol. Cell. Biol. (1994) 14:2411, and in Woffendin, Proc. Natl. Acad. Sci. (1994) 91:1581.

It is also apparent that an expression vector can be used to direct expression of any of the protein-based IL-20 antagonists described herein (e.g., anti-IL-20 antibody, or anti-IL-20R antibody). For example, other IL-20 receptor fragments that are capable of blocking (from partial to complete blocking) IL-20 and/or an IL-20 biological activity are known in the art.

The particular dosage regimen, i.e., dose, timing and repetition, used in the method described herein will depend on the particular subject and that subject's medical history.

In some embodiments, more than one IL-20 antagonist, such as an antibody and a small molecule IL-20 inhibitory compound, may be administered to a subject in need of the treatment. The antagonist can be the same type or different from each other. At least one, at least two, at least three, at least four, at least five different IL-20 antagonists can be co-administered. Generally, those IL-20 antagonists have complementary activities that do not adversely affect each other. IL-20 antagonists can also be used in conjunction with other agents that serve to enhance and/or complement the effectiveness of the agents.

Treatment efficacy can be assessed by methods well-known in the art, e.g., monitoring the levels of AST and/or ALT in a patient subjected to the treatment. See, e.g., Example 2 below.

Kits for Use in Alleviating Liver Fibrosis

The present disclosure also provides kits for use in alleviating liver fibrosis/cirrhosis. Such kits can include one or more containers comprising an IL-20 antagonist (such as an antibody, e.g., mAb7E or its functional variant, mAb7GW or its functional variant, or mAb51D or its functional variant). In some embodiments, the IL-20 antagonist is any antibody capable of interfering with the IL-20 signaling pathway as described herein. In other embodiments, the kit comprises an IL-20 antagonist that is other than the just-noted antibody.

In some embodiments, the kit can comprise instructions for use in accordance with any of the methods described herein. The included instructions can comprise a description of administration of the IL-20 antagonist to treat, delay the onset, or alleviate liver fibrosis/cirrhosis according to any of the methods described herein. The kit may further comprise a description of selecting an individual suitable for treatment based on identifying whether that individual has liver fibrosis. In still other embodiments, the instructions comprise a description of administering an IL-20 antagonist to an individual at risk of liver fibrosis.

The instructions relating to the use of an IL-20 antagonist generally include information as to dosage, dosing schedule, and route of administration for the intended treatment. The containers may be unit doses, bulk packages (e.g., multi-dose packages) or sub-unit doses. Instructions supplied in the kits of the invention are typically written instructions on a label or package insert (e.g., a paper sheet included in the kit), but machine-readable instructions (e.g., instructions carried on a magnetic or optical storage disk) are also acceptable.

The label or package insert indicates that the composition is used for treating, delaying the onset and/or alleviating liver fibrosis or cirrhosis. Instructions may be provided for practicing any of the methods described herein.

The kits of this invention are in suitable packaging. Suitable packaging includes, but is not limited to, vials, bottles, jars, flexible packaging (e.g., sealed Mylar or plastic bags), and the like. Also contemplated are packages for use in combination with a specific device, such as an inhaler, nasal administration device (e.g., an atomizer) or an infusion device such as a minipump. A kit may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). The container may also have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). At least one active agent in the composition is an IL-20 antagonist, such as an anti-IL-20 antibody.

Kits may optionally provide additional components such as buffers and interpretive information. Normally, the kit comprises a container and a label or package insert(s) on or associated with the container. In some embodiments, the invention provides articles of manufacture comprising contents of the kits described above.

Without further elaboration, it is believed that one skilled in the art can, based on the above description, utilize the present invention to its fullest extent. The following specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. All publications cited herein are incorporated by reference for the purposes or subject matter referenced herein.

Example 1 Association of IL-20 with Liver Diseases Materials and Methods Clinical Specimen

Liver biopsy samples were obtained from six patients in the National Cheng Kung University Hospital (Tainan, Taiwan), included three cases of liver fibrosis (early stage) and three cases of liver cirrhosis (late stage of liver fibrosis). Liver samples of three normal patients were purchased from SUPER BIO CHIPS. Eleven non-cirrhosis liver tissue and 9 cirrhosis liver tissue were analyzed by real-time PCR as described below.

Expression and Purification of Rat IL-20 Recombinant Protein

A fragment of the rat IL-20 (GenBank accession no. NM_(—)001143881.1 or GI:219842194), from Leu₂₅ to Leu₁₇₆, was amplified by PCR and inserted into the pSecTag2A vector. The resultant plasmid was introduced into 293T cells for expression of the rat IL-20 protein. The expressed protein was purified using metal affinity chromatography.

Cell Culture

Rat hepatocyte Clone-9 cells, a normal cell line, were purchased from American Type Culture Collection. These cells were cultured in DMEM/F12 medium (Hyclone) containing 10% FBS.

Primary rat hepatic stellate cells (rHSC) were isolated from male Sprague-Dawley rats by in situ enzymatic digestion of the liver and gradient ultracentrifugation as described previously. Corazza et al., Semin Immunopathol., 2009, 31(2):267-77. The isolated rHSC cells were maintained in DMEM/HG (Hyclone) containing 10% FBS.

Cells were cultured in 1% medium before treatment and then exposed to various conditions as described herein.

IL-20 Functional Assay and Neutralization Ability of mAb7E and mAb51D

Clone-9 cells and rHSC cells were treated with (a) rat IL-20 (200 ng/ml), (b) mAb7E (2 μg/ml), (c) rat IL-20 (200 ng/ml) and mAb7E (2 μg/ml), (d) mAb51D (2 μg/ml), (e) rat IL-20 (200 ng/ml) and mAb51D (2 μg/ml), (f) mIgG (2 μg/ml), and (g) rat IL-20 (200 ng/ml) and a control mIgG (2 μg/ml) for various times.

Immunocytochemical (IHC) Staining for Paraffin Sections and Cultured Cells

The paraffin on sections were removed using xylene and rehydrated using a graded ethanol series. Cells were fixed in 3.7% paraformaldehyde and then permeabilized using PBS with 0.1% Triton X-100. The sections and cells were blocked by immersing them in an antibody diluent with background reducing components (DakoCytomation) and then incubated with the primary antibody in a blocking reagent. The following procedure was performed according to the instruction of romulin AEC chromogen kit (Biocare) and counterstained with Mayer's hematoxylin (J.T. Backer). The antibodies used in this assay were purchased as follows: antibodies specific to IL-20R1, IL-20R2, IL-22R1 and a mIgG isotype control were obtained from R&D system; antibodies specific to PCNA were obtained from Genetex.0

Reverse Transcription PCR (RT-PCR) and Real-Time PCR

Total RNAs were extracted from cells or tissues using Trizol reagent (Life Technologies) and underwent reverse transcription according to the manufacturer's instructions. The expression levels of mRNAs were analyzed using amplified PCR and real-time PCR with gene-specific primers. GAPDH was as an internal control.

Detection of amplified PCR products was accomplished with SYBR Green I (Roche) chemistry using a fluorescence detection system (LightCycler 480; Roche). The specific primers used in real-time PCR were the same as those used in amplified PCR. The level of GAPDH was as internal control.

Cell Cycle Analysis

Clone-9 cells were treated with A conditional medium for 24 hours. After the treatment, the cells were collected and washed with PBS, then fixed with 70% ethanol, and stored at 4° C. for 24 hours. After being washed three times with cold PBS, the cell were stained with 100 μg/ml PI and 50 μg/ml DNase-free RNase A for 10 min. DNA fluorescence of PI-stained cells was evaluated by using a FACScan flow cytometer (Becton Dickinson). The percentages of cells in sub-G₀/G₁ and G₂/M phase were quantitated using WinMDI 2.8 software.

Western Blotting Analysis

Clone-9 cell lysates were prepared using a cell lysis buffer (Cell signaling). Western blotting was using specific primary antibodies against p21^(wAFI) (Genetex) following the manufacturer's instructions β-actin was used as an internal control.

Cell Proliferation Assay

The proliferation of primary rHSC cells were determined by the MTT assay. After being incubated in the conditional medium for 72 hours, the cells were mixed with a solution of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT; Sigma) at a concentration of 0.5 mg/mL for 3 hours. The supernatant was aspirated, and DMSO (Sigma) was added to dissolve the blue crystals. Absorbance of 550 nm was determined.

Migration Assays

The level of rHSC migration was examined using a Boyden chamber housing a polycarbonate filter with 8 μm pores (Nucleopore). The upper wells were loaded with 10⁴ rHSC. The lower chambers were filled with the condition medium. The chamber was incubated for 8 hours at 37° C. Cells adhering to the lower side of the filter were fixed in 100% methanol and stained with Liu's staining (TonyarBiotech). The number of the cells on the lower surface of the filter was determined microscopically by counting 15 randomly selected fields.

Results IL-20 is Highly Expressed in Liver Diseases

To examine whether IL-20 was involved in the pathogenesis of liver diseases, the expression levels of IL-20 in the liver biopsies from patients with fibrosis, cirrhosis, and hepatocellular carcinoma were determined using immunohistochemistry staining. IL-20 was highly expressed in hepatic stellate cells as well as in hepatocytes of fibrosis patients, cirrhosis patients, and hepatocellular carcinoma patients. No IL-20 overexpression was observed in non-cirrhosis samples. These results indicate that the level of IL-20 expression is highly associated with liver fibrosis such as liver cirrhosis.

IL-20 Induced TGF-⊖1 Expression in Clone-9 Cells

To explore if higher expression of IL-20 in hepatocytes was associated with the pathogenesis of liver fibrosis/cirrhosis, the effects of IL-20 on normal rat hepatocytes cells, Clone-9, were examined.

The IL-20 expression was analyzed using real-time PCR. RT-PCR and immunohistochemical (IHC) staining showed that both IL-20 and its receptor were expressed in Clone-9 cells. These results suggested that IL-20 could act in an autocrine manner on hepatocyte cells.

The cytotoxic effect of CCl₄ on Clone-9 cells was studied as follows. Clone-9 cells were incubated with CCl₄ (10 g M) for the indicated time periods. CCl₄ treatment induced IL-20 expression in Clone-9 cells. TGF-β1 is a key factor for hepatocyte proliferation. To examine the effect of IL-20 on hepatocyte cells, the expression of TGF-β1 mRNA was analyzed in Clone-9 cells. IL-20 increased the TGF-β1 mRNA levels. FIG. 1. Moreover, the anti-IL-20 monoclonal antibody mAb7E and anti-IL-20R1 monoclonal antibody mAb51D effectively neutralized the induction of TGF-β1 expression by IL-20 in Clone-9 cells. FIG. 1.

IL-20 Increased Cell Cycle Arrest by Upregulating p21^(WAF1) in Clone-9 Cells

TGF-β1 can inhibit cell cycle progression by causing G1/S arrest and upregulating p21^(WAF1) expression. Albrecht et al., Oncogene. 1998, 16(16):2141-50; Li et al., J Biol Chem. 1995, 270(10):4971-4; and Datto et al., Proc Natl Acad Sci USA. 1995, 92(12):5545-9. A flow cytometry assay as described herein was performed to examine whether IL-20 can affect cell cycle distribution. The results indicate that IL-20 increased the percentage of cells arrested in the G0/G1 phase of the cell cycle at 24 h and this IL-20-induced cell cycle arrest was rescued by mAb7E and mAb51D. Furthermore, IL-20 significantly increased the expression level of cell cycle inhibitor p21^(WAF1) in Clone-9 cells. This IL-20-induced p21^(WAF1) overexpression was again neutralized by mAb7E and mAb51D. These results suggest that IL-20 can induce TGF-β expression and impair hepatocyte proliferation by upregulating p21^(WAF1), leading to the progression of liver fibrosis. Antibodies against IL-20 and IL-20 receptor IL-20R1 were found in this study to reverse this process.

IL-20 Induced Primary Rat HSCs Activation

HSCs are the main cell population in the liver. Such cells are responsible for increased deposition of extracellular matrix proteins. HSCs must be activated to transform from resting, fat-storing cell type into myofibroblast-like cells, which then synthesize a broad spectrum of extracellular matrix protein. Activated HSCs that express α-SMA are responsible for fibrosis and sinusoidal component of portal hypertension by depositing excessive amounts of ECM of abnormal composition and increased contractility. Bataller et al., J Clin Invest. 2005, 115(2):209-18; Crary et al., Hepatology, 1998, 28(3):738-43; and Pinzani et al., Semin Liver Dis. 1999; 19(4):397-410.

Primary rat HSC cells cultured less than 48 hours, representing a “quiescent” phenotype, and primary rHSC cells cultured for 10-14 days, representing an “activated” phenotype, were used in this study. See Sommerfeld et al., J Biol Chem. 2009, 284(33):22173-83.

To determine whether IL-20 was involved in rat HSC activation, IL-20 and α-SMA mRNA levels of rat HSC cells cultured for 1 day (passage 0), 7 days (passage 1), and 20 days (passage 3) were analyzed by real-time PCR. The results show that the levels of IL-20 and α-SMA mRNAs were up-regulated during the activation process of quiescent rat HSCs. To confirm the effect of IL-20 in quiescent rat HSC activation, α-SMA and TGF-β mRNA levels in quiescent rat HSC cells treated with IL-20 were analyzed by using real-time PCR. IL-20 increased the mRNA levels of α-SMA, as well as TGF-β, TNF-α, and Col-I and mAb7E and mAb51D neutralized this activity. See, e.g., FIG. 2.

IL-20 Upregulated TGF-β1 Expression and Stimulated TNF-α Expression, Proliferation and Migration in Activated HSC

To detect the TGF-β expression in activated rat HSC cells treated with IL-20, TGF-β mRNA levels were analyzed by real-time PCR. The results show that TGF-β mRNA levels were increased in activated rat HSC cells treated with IL-20 and the IL-20-induced expression was inhibited by mAb7E and mAb51D. IL-20 also upregulated the expression of inflammatory cytokine TNF-α, ECM component Col-I. Again, the IL-20-induced overexpression of these proteins was inhibited by mAb7E and mAb51D.

The proliferation and migration activities in the activated rat HSC treated with IL-20 were analyzed by using the Boyden chamber and MTT assay. IL-20 regulated the migration activity and proliferation of activated rat HSC cells.

Taken together, the above results show that IL-20 increased the expression of TGF-β, TNF-α, improved ECM formation, and enhanced cell proliferation and migration in activated rHSC. These IL-20-induced activities were inhibited by mAb7E and mAb51D.

Example 2 Protective Effect of Anti-IL-20 and Anti-IL-20R1 Antibodies in a CCl4-Induced Liver Injury Mouse Model Materials and Methods CCL₄-Induced Liver Injury Animal Model

Ten to twelve-week old C57BL/6J, IL-20R1^(+/+), IL-20R1^(+/−), or IL-20R1^(−/−) mice were used in this study. Each experimental group includes three to five mice. For short-term CCl₄-induced liver injury, a single dose of 1 ml/kg of body weight (1:5 v/v in mineral oil) of CCl₄ was administered into mice by intraperitoneal (I.P.) injection. For long-term CCl₄-induced liver injury, a dose of 1 ml/kg of body weight of CCl₄ was administered into mice via IP twice per week for 8 week. The control mice were injected with similar volumes of olive oil.

Antibody Treatments

C57BL/6J mice having short-term CCl₄-induced liver injury were subcutaneously injected with 3 mg/kg mAb7E once per day after CCl₄ administration or pre-injected 6 mg/kg mAb51D once per day before CCl₄ administration for 3 days. The first mAb7E injection was performed at 1 hour after CCl₄ treatment and the first mAb51D injection was performed at 1 hour before CCl₄ treatment.

C57BL/6J mice having long-term CCl₄-induced liver injury were injected with 3 mg/kg mAb7E after CCl₄ administration or pre-injected 6 mg/kg mAb51D before CCl₄ administration. The control group of mice was subcutaneously injected with the same volume of a control mIgG (Peprotech).

Histology

Paraffin sections of the liver were stained by hematoxylin and eosin (H&E). A Sirius red stain of paraffin section was used to qualitatively assess collagen architecture and extent of fibrosis. To quantify fibrosis formation as previously described.

Liver Hydroxyproline Determination

The total amount of hydroxyproline expressed in a liver tissue, which serves as a quantitative measure of collagen deposition and fibrosis, were determined following the methods described in Friedman et al., Gastroenterology. 2008, 134(6):1655-69; and Oh et al., Apoptosis. 2007, 12(7):1339-47 with modifications. Briefly, a frozen liver tissue sample (50-60 mg) was hydrolyzed at 110° C. in 6N HCl for 12 hours. The hydrolysate was dissolved in 50% isopropanol and incubated with 0.84% chloramine-T in 42 mmol/L sodium acetate. Relative hydroxyproline (mg/g liver) was then quantified photometrically at 560 nm. Hydroxyproline contents of each individual tissue are expressed as μg hydroxyproline/mg tissue wet weight.

Serum Aspartate Aminotransferase and Alanine Amino Transferase

The liver function in mice having CCl₄-induced liver injury was monitored by measuring the levels of aspartate aminotransferase (AST) and alanine amino transferase (ALT). The activities of these two enzymes were expressed as unit per liter (U/L).

Enzyme-Linked Immunosorbent Assay (ELISA)

The serum level of IL-20 in mice having CCl₄-induced liver injury was measured by enzyme-linked immunosorbent assay kit (R&D system) according to the manufacturer's instructions.

Results

Anti-IL-20 and Anti-IL-20R1 Antibodies Protected Mice from Short-Term CCl₄-Induced Liver Injury

CCl₄-induced liver injury has been used as a hepatotoxin animal model for studying induced cirrhotic responses in animals, which mimic human liver fibrosis/cirrhosis. Therefore, the CCl₄-induced liver injury animal model was extensively used to evaluate the therapeutic potentials of drugs and dietary antioxidants. Hsu et al., Food Chem Toxicol. 2010, 48(6):1644-53.

To further confirm that IL-20 was involved in hepatocyte damage and the antagonist of IL-20 can effectively neutralized the IL-20 activity in liver diseases, mice having the short-term CCl₄-induced liver injury were analyzed for the protective effects of mAb7E and mAb51D. CCl₄-induced short-term liver injury mice were sacrificed 3 days after the CCl₄ injection. Serum IL-20 levels were found to be significantly increased in these mice.

The protective effects of mAb7E and mAb51D in short-term CCl₄-induced liver injury mice were analyzed by subcutaneous injection of the antibodies after CCl₄ administration. The levels of AST and ALT were measured at 24 h, 48 h and 72 h, after the administration of CCl₄. The serum levels of ALT and AST rapidly elevated to reach a peak at 24 h in the short-term CCl₄-induced liver injury mice. FIG. 3. mAb 7E treatment significantly inhibited the elevation of ALT and AST activities from 24 h to 72 h, as compared to the control group. FIG. 3A and FIG. 3B. The mRNA levels of TGF-β, a cell cycle regulator, in liver tissues and serum were measured by ELISA and real-time PCR. The reduction of the TGF-β level and serum AST and ALT levels indicated that mAb7E and mAb51D protected the hepatocyte from CCl₄-induced liver injury.

Immunochemistry staining of PCNA in liver sections were performed at 72 h to investigate hepatocyte proliferation. The amount of PCNA-positive cells was found to increase in the liver sections isolated from mice treated with mAb7E and mAb51D after the CCl₄ administration. Greater amount of hepatocyte were detected in mice treated with mAb7E and mAb51D, as compared to mice treated with the control mIgG, indicating that mAb7E and mAb51D significantly increased the number of PCNA cells.

Lymphocyte recruitment to the liver is a characteristic of inflammation. Adams et al., Lancet. 1997, 349(9050):490-5. The expression levels of chemokines MCP-1, KC, and MIP-2β, in the liver tissues were examined by real-time PCR. The results indicate that mAb7E and mAb51D antibodies significantly reduced inflammatory infiltrates and decreases inflammatory responses in the liver tissues.

Anti-IL-20 and Anti-IL-20R1 Antibodies Protected Mice from Long-Term CCl₄-Induced Liver injury

To test the therapeutic potentials of mAb7E and mAB51D in long-term liver injury, the mice model of long-term CCl₄-induced liver injury as described herein was used in this study. Long-term CCl₄-induced liver injury mice were sacrificed 8 weeks after the CCl₄ administration. Serum levels of IL-20 in these mice were also increased after the CCl₄ administration.

As noted above, TGF-β can up-regulate the production and deposition of ECM, which can result in the progression of liver fibrosis. Here, the TGF-β mRNA levels in liver tissues and TGF-β protein levels in the sera were also measured by real-time PCR and ELISA. The results indicate that mAb7E and mAb51D reduced TGF-β expression in long-term CCl₄-induced liver injury mice, as compared to the control mice.

Treatment with mAb7E and mAb51D in the mice of long-term CCl₄-induced liver injury significantly decreased the ALT and AST levels in the sera of these mice, as compared to the control mice. FIG. 4. This result was consistent with the results obtained from hepatic histology assays via H&E staining.

Long-term CCl₄-induced liver injury resulted in liver fibrosis as shown by Sirius red staining. To directly quantify the degree of fibrosis, total liver collagen was determined by measuring the hepatic hydroxyproline content. Both mAb7E and mAb51D were found to significantly reduce the total hepatic hydrozyproline content in the long-term CCl₄-induced liver injury mice as compared to mice treated with an mIgG control.

Liver fibrosis results into activation of quiescent HSCs as characterized by α-SMA expression. The α-SMA mRNA level was analyzed by real-time PCR in the long-term CCl₄-induced liver injury mouse model. The results indicate that both mAb7E and mAb51D significantly inhibited HSC activation as compared to the mice treated with the control mIgG.

Activated HSCs release TGF-β and increase chemotaxis. The levels of TNF-α and MCP-1 mRNAs were measured by real-time PCR. It was found that the expression of TNF-α and MCP-1 was elevated and both mAb7E and mAb51D suppressed the overexpression of these proteins in the long-term CCl₄-induced liver injury mice.

The expression of TIMPs in activated HSCs was up-regulated, leading to the inhibition of MMP activity and subsequent accumulation of matrix proteins in the extracellular space. Schuppan et al., Semin Liver Dis. 2001, 21(3):351-72. TIMP-1, TIMP-2, MMP-2 and MMP-12 mRNA levels were analyzed by using real-time PCR. Results obtained from this study show that mAb7E and mAb51D decreased the expression of TIMPs and reversed the expression of MMPs.

The above-results clearly show that mAb7E and mAb51D significantly protected mice from CCl₄-induced short-term and long-term liver injury, indicating that these antibodies are effective in alleviating liver fibrosis/cirrhosis and treating liver diseases.

Example 3 IL-20R1 Knock-Out Mice are Resistant to Short-Term and Long-Term CCl₄-Induced Liver Injury

The effect of IL-20R1-deficiency on IL-20-induced liver injury was analyzed. IL-20R1^(+/+) mice and IL-20R1^(−/−) mice were treated with CCl₄ following the protocols described above to induce short-term liver injury. The level of TGF-β mRNA in the liver tissue of the treated mice and TGF-β protein levels in the serum of the treated mice were measured by real-time PCR and ELISA, respectively. The enzymatic activities of AST and ALT were also measured at 24 h, 48 h, and 72 h. IL-20R1^(−/−) mice showed significantly lower TGF-β levels and serum AST and ALT activities as compared to IL-20R1^(+/+) mice. The PCNA cells in IL-20R1^(−/−) mice were much less than those in IL-20R1^(+/+) mice.

The expression levels of inflammatory chemokines MCP-1, KC and MIP-2β in the liver tissues of the treated mice were also determined by real-time PCR. The levels of these chemokines were significantly decreased in IL-20R1^(−/−) mice compared to the wild type mice, indicating that liver inflammation was significantly decreased in IL-20R1-deficient mice.

IL-20R1^(+/+) mice and IL-20R1^(−/−) mice were also treated with CCl₄ to induce long-term liver injury following the protocol described above. After eight weeks of the CCl₄ administration, the TGF-β levels and serum AST and ALT levels were significantly lower in IL-20R1^(−/−) mice than in IL-20R1^(+/+) mice. These results were consistent with the hepatic histology assay via H&E staining. Eight weeks treatment of CCl₄ caused occurrence of hepatic fibrosis in mouse liver as analyzed by Sirius red staining. IL-20R1 deficiency resulted in a significantly decreased level of the total collagen (hydroxyproline) content as compared to that of IL-20R1^(+/+) mice.

The mRNA levels of α-SMA, Col-I, VEGF-1, TNF-ct, TIMP-3, TIMP-4, MMP-2, MMP-12 and MMP-13 were analyzed using real-time PCR. IL-20R1^(−/−) mice showed significant decreased expression of these proteins relative to IL-20R1^(+/+) mice.

OTHER EMBODIMENTS

All of the features disclosed in this specification may be combined in any combination. Each feature disclosed in this specification may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each feature disclosed is only an example of a generic series of equivalent or similar features.

From the above description, one skilled in the art can easily ascertain the essential characteristics of the present invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Thus, other embodiments are also within the claims. 

1. A method for alleviating or delaying the onset of liver fibrosis in a subject, comprising administering to a subject in need thereof an effective amount of an IL-20 antagonist, wherein the IL-20 antagonist is an antibody binding to a human IL-20 receptor. 2-10. (canceled)
 11. The method of claim 1, wherein the antibody binds subunit R1 of the human IL-20 receptor.
 12. The method of claim 11, wherein the antibody is a full-length antibody or an antigen-binding fragment thereof.
 13. The method of claim 12, wherein the antibody is a human antibody, a humanized antibody, a chimeric antibody, or a single-chain antibody.
 14. The method of claim 11, wherein the antibody that binds subunit R1 of the human IL-20 receptor is an antibody comprising the same V_(H) and V_(L) chain as monoclonal antibody mAb51D or mAb7GW, or a functional variant thereof.
 15. The method of claim 14, wherein the functional variant comprises the same complementary determining regions (CDRs) as mAb51D or mAb7GW.
 16. The method of claim 15, wherein the functional variant is a humanized antibody of mAb51D or mAb7GW.
 17. The method of claim 1, wherein the subject is a human patient having or being suspected of having liver fibrosis.
 18. The method of claim 17, wherein the liver fibrosis is associated with chronic HBV infection, chronic HCV infection, alcohol abuse, nonalcoholic steatohepatitis, autoimmune hepatitis, primary biliary cirrhosis, fatty liver disease, or an idiopathic liver disease.
 19. The method of claim 17, wherein the subject is a human patient having or being suspected of having liver cirrhosis. 20-21. (canceled) 